Multidimensional beam refinement procedures and signaling for mmwave wlans

ABSTRACT

Systems and methods for multidimensional beam refinement procedures and signaling for millimeter wave WLANs. In some embodiments, there are multi-dimensional enhanced beam refinement protocol MAC and PHY frame designs that extend the MAC packet and the PPDU format with or without backwards compatibility. The multiple dimensions may be supported jointly or separately. In other embodiments, the increased data signaled in the eBRP frame designs may be more efficiently signaled with reduced BRP frame sizes, such as through a training type dependent BRP minimum duration selection procedure or use of null data packet BRP frames. In further embodiments, the maximum duration of the interframe spacing between BPR packets may be varied to improve the efficiency of BRP operation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 17/230,473, filed Apr. 14, 2021, which is a continuation ofU.S. Non-Provisional application Ser. No. 16/346,619, filed May 1, 2019,which issued as U.S. Pat. No. 10,985,826 on Apr. 20, 2021, which is aNational Stage entry under 35 U.S.C. § 371 of Patent Cooperation TreatyApplication PCT/US17/59765, filed Nov. 2, 2017, which claims the benefitof U.S. Provisional Application No. 62/500,421, filed May 2, 2017, U.S.Provisional Application No. 62/445,642, filed Jan. 12, 2017, and U.S.Provisional Application No. 62/417,145, filed Nov. 3, 2016, the entirecontents of each of which are incorporated by reference herein.

BACKGROUND Overview of WLAN System.

A WLAN in Infrastructure Basic Service Set (BSS) mode has an AccessPoint (AP/PCP) for the BSS and one or more stations (STAs) associatedwith the AP/PCP. The AP/PCP typically has access or interface to aDistribution System (DS) or another type of wired/wireless network thatcarries traffic in and out of the BSS. Traffic to STAs that originatesfrom outside the BSS arrives through the AP/PCP and is delivered to theSTAs. Traffic originating from STAs to destinations outside the BSS issent to the AP/PCP to be delivered to the respective destinations.Traffic between STAs within the BSS may also be sent through the AP/PCPwhere the source STA sends traffic to the AP/PCP and the AP/PCP deliversthe traffic to the destination STA. Such traffic between STAs within aBSS is really peer-to-peer traffic. Such peer-to-peer traffic may alsobe sent directly between the source and destination STAs with a directlink setup (DLS) using an 802.11e DLS or an 802.11z tunneled DLS (TDLS).A WLAN using an Independent BSS (IBSS) mode has no AP/PCP, and/or STAs,communicating directly with each other. This mode of communication isreferred to as an “ad-hoc” mode of communication.

Using the 802.11ac infrastructure mode of operation, the AP/PCP maytransmit a beacon on a fixed channel, usually the primary channel. Thischannel may be 20 MHz wide, and is the operating channel of the BSS.This channel is also used by the STAs to establish a connection with theAP/PCP. The fundamental channel access mechanism in an 802.11 system isCarrier Sense Multiple Access with Collision Avoidance (CSMA/CA). Inthis mode of operation, every STA, including the AP/PCP, will sense theprimary channel. If the channel is detected to be busy, the STA backsoff. Hence only one STA may transmit at any given time in a given BSS.

In 802.11n (see, IEEE Standard 802.11™-2012: Wireless LAN Medium AccessControl (MAC) and Physical Layer (PHY) Specifications), High Throughput(HT) STAs may also use a 40 MHz wide channel for communication. This isachieved by combining the primary 20 MHz channel, with an adjacent 20MHz channel to form a 40 MHz wide contiguous channel.

In 802.11ac (see, IEEE Std 802.11ad™-2012: Part 11: Wireless LAN MediumAccess Control (MAC) and Physical Layer (PHY) Specifications Amendment3: Enhancements for Very High Throughput in the 60 GHz Band), Very HighThroughput (VHT) STAs may support 20 MHz, 40 MHz, 80 MHz, and 160 MHzwide channels. The 40 MHz, and 80 MHz, channels are formed by combiningcontiguous 20 MHz channels similar to 802.11n described above. A 160 MHzchannel may be formed either by combining 8 contiguous 20 MHz channels,or by combining two non-contiguous 80 MHz channels, this may also bereferred to as an 80+80 configuration. For the 80+80 configuration, thedata, after channel encoding, is passed through a segment parser thatdivides it into two streams. IFFT, and time domain, processing are doneon each stream separately. The streams are then mapped on to the twochannels, and the data is transmitted. At the receiver, this mechanismis reversed, and the combined data is sent to the MAC.

Sub 1 GHz modes of operation are supported by 802.11af (see, IEEE802.11-10/0258r0, MAC and PHY Proposal for 802.11af, March 2010), and802.11ah (see, IEEE 802.11-10/0001r13, Sub 1 GHz license-exempt PAR and5C, July 2010). For these specifications, the channel operatingbandwidths and carriers are reduced relative to those used in 802.11nand 802.11ac. 802.11af supports 5 MHz, 10 MHz and 20 MHz bandwidths inthe TV White Space (TVWS) spectrum, and 802.11ah supports 1 MHz, 2 MHz,4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. A possibleuse case for 802.11ah is support for Meter Type Control (MTC) devices ina macro coverage area. MTC devices may have limited capabilitiesincluding only support for limited bandwidths, but also include arequirement for a very long battery life.

WLAN systems which support multiple channels and channel widths, such as802.11n, 802.11ac, 802.11af, and 802.11ah, include a channel which isdesignated as the primary channel. The primary channel may, but does notnecessarily, have a bandwidth equal to the largest common operatingbandwidth supported by all STAs in the BSS. The bandwidth of the primarychannel is therefore limited by the STA, of all STAs in operating in aBSS, which supports the smallest bandwidth operating mode. In theexample of 802.11ah, the primary channel may be 1 MHz wide if there areSTAs (e.g., MTC type devices) that only support a 1 MHz mode even if theAP/PCP, and other STAs in the BSS, may support a 2 MHz, 4 MHz, 8 MHz, 16MHz, or other channel bandwidth operating modes. All carrier sensing,and NAV settings, depend on the status of the primary channel; i.e., ifthe primary channel is busy, for example, due to a STA supporting only a1 MHz operating mode is transmitting to the AP/PCP, then the entireavailable frequency bands are considered busy even though majority of itstays idle and available.

In the United States, the available frequency bands which may be used by802.11ah are from 902 MHz to 928 MHz. In Korea it is from 917.5 MHz to923.5 MHz; and in Japan, it is from 916.5 MHz to 927.5 MHz. The totalbandwidth available for 802.11ah is 6 MHz to 26 MHz depending on thecountry code.

To improve spectral efficiency 802.11ac has introduced the concept fordownlink Multi-User MIMO (MU-MIMO) transmission to multiple STA's in thesame symbol's time frame, e.g., during a downlink OFDM symbol. Thepotential for the use of downlink MU-MIMO is also currently consideredfor 802.11ah. It is important to note that since downlink MU-MIMO, as itis used in 802.11ac, uses the same symbol timing to multiple STA'sinterference of the waveform transmissions to multiple STA's is not anissue. However, all STA's involved in MU-MIMO transmission with theAP/PCP must use the same channel or band, this limits the operatingbandwidth to the smallest channel bandwidth that is supported by theSTA's which are included in the MU-MIMO transmission with the AP/PCP.

802.11ad.

802.11 ad is an amendment to the WLAN standard, which specifies the MACand PHY layers for very high throughput (VHT) in the 60 GHz band.

802.11ad has the following important features

-   -   Support data rates up to 7 Gbits/s    -   Support three different modulation modes        -   Control PHY with single carrier and spread spectrum        -   Single Carrier PHY        -   OFDM PHY    -   Use 60 GHz unlicensed band, which is available globally. At 60        GHz, the wavelength is 5 mm, which makes compact and antenna or        antenna arrays possible. Such an antenna can create narrow RF        beams at both transmitter and receiver, which effectively        increase the coverage range and reduce the interference.    -   The frame structure of 802.11ad facilitates a mechanism for        beamforming training (discovery and tracking). The beamforming        training protocol comprises of two components: a sector level        sweep (SLS) procedure, and a beam refinement protocol (BRP)        procedure. The SLS procedure is used for transmit beamforming        training; the BRP procedure enables receive beamforming        training, and iterative refinement of both the transmit and        receive beams.

MIMO transmissions, including both SU-MIMO and MU-MIMO, are notsupported by 802.11ad.

802.11ad PPDU Formats. 802.11ad supports three PPDU formats, which areControl PHY, Single Carrier (SC) PHY, and OFDM PHY PPDUs. The PPDUformats, as defined in IEEE Std 802.11ad™-2012: Part 11: Wireless LANMedium Access Control (MAC) and Physical Layer (PHY) SpecificationsAmendment 3: Enhancements for Very High Throughput in the 60 GHz Band,are shown in FIG. 1 . FIG. 1 illustrates a control format 12, a singlecarrier format 14, and an OFDM format 16.

802.11ad Control PHY. Control PHY is defined in 802.11ad as the lowestdata rate transmission. Frames which are transmitted before beamformingtraining may use Control PHY PPDU. For 802.11ad, the transmission blockdiagram of Control PHY is shown in FIG. 2 .

Sector Level Sweep. An exemplary SLS training procedure is shown in FIG.3 . SLS training may be performed using a Beacon frame or SSW frame.When the Beacon frame is utilized, the AP repeats the Beacon frame withmultiple beams/sectors within each Beacon interval (BI) and multipleSTAs can perform BF training simultaneously. However, due to the size ofBeacon frame, it is no guarantee that the AP can sweep all thesectors/beams within one BI. Thus, an STA may need to wait for multipleBIs to complete ISS training, and latency may be an issue. An SSW framemay be utilized for point-to-point BF training. An SSW frame may betransmitted using control PHY, and the frame format is shown in FIG. 4 .The SSW field is defined in FIG. 4 with the field format defined in FIG.5 . The SSW Feedback field is given in FIGS. 6A and 6B.

Beam Refinement Protocol (BRP). Beam refinement is a process where a STAcan improve its antenna configuration (or antenna weight vectors) bothfor transmission and reception. In the beam refinement procedure, BRPpackets are used to train the receiver and transmitter antenna. Thereare two types of BRP packets: BRP-RX packets and BRP-TX packets. BRPpacket may be carried by a directional multi-gigabit (DMG) physicallayer (PHY) protocol data unit (PPDU) followed by a training fieldcontaining an AGC field and a transmitter or receiver training field asshown in FIG. 7 .

A value of N in FIG. 7 is the Training Length given in the header filed,which indicates that the AGC has 4N subfields and that the TRN-R/T fieldhas 5N subfields. The CE subfield is the same as the one in the preambledescribed in the previous section. All subfields in the beam trainingfield are transmitted using rotated π/2-BPSK modulation.

BRP MAC frame is an Action No ACK frame, which has the following fields:

-   -   Category    -   Unprotected DMG Action    -   Dialog Token    -   BRP Request field    -   DMG Beam Refinement element    -   Channel Measurement Feedback element 1    -   . . .    -   Channel Measurement Feedback element k

802.11ay (TGay).

Requirements of 802.11ay. Task Group ay (TGay), approved by IEEE inMarch 2015, is expected to develop an amendment that definesstandardized modifications to both the IEEE 802.11 physical layers (PHY)and the IEEE 802.11 medium access control layer (MAC) that enables atleast one mode of operation capable of supporting a maximum throughputof at least 20 gigabits per second (measured at the MAC data serviceaccess point), while maintaining or improving the power efficiency perstation. This amendment also defines operations for license-exempt bandsabove 45 GHz while ensuring backward compatibility and coexistence withlegacy directional multi-gigabit stations (defined by IEEE 802.11ad-2012 amendment) operating in the same band.

Although much higher maximum throughput than that of 802.11ad is theprimary goal of TGay, some members of the group also proposed to includemobility and outdoor support. More than ten different use cases areproposed and analyzed in terms of throughput, latency, operationenvironment and applications (see, IEEE 802.11-2015/0625r2, “IEEE 802.11TGay Use Cases”, Huawei, et. al).

Since 802.11ay will operate in the same band as legacy standards, it isrequired that the new technology will ensure backward compatibility andcoexistence with legacies in the same band.

802.11ay PPDU Format. It has been agreed that 802.11ay PPDU containlegacy part and EDMG part. The detailed PPDU format is shown in FIG. 8 .

The legacy short training field (L-STF), legacy channel estimation field(L-CEF), L-Header and EDMG-Header-A fields are transmitted using SC modefor backward compatibility. It was agreed in the IEEE January 2016meeting that

-   -   For a control mode PPDU, the reserved bits 22 and 23 shall be        both set to 1 to indicate the presence of the EDMG-Header-A        field.    -   For a SC mode PPDU or an OFDM mode PPDU, the reserved bit 46        shall be set to 1 to indicate the presence of the EDMG-Header-A        field.

Millimeter Wave Precoding. Precoding at millimeter wave frequencies maybe digital, analog or a hybrid of digital and analog (see, MIMOPrecoding and Combining Solutions for mmWave Systems: Alkahteeb, Mo.,Gonzalez-Prelcic, Heath, 2014).

Digital precoding: Digital precoding is precise and can be combined withequalization. It enables single user (SU), multi-user (MU), andmulti-cell precoding, and is typically used in sub 6 GHz, for example inIEEE 802.11n and beyond and in 3GPP LTE and beyond. However, inmillimeter wave frequencies, the presence of a limited number of RFchains compared with antenna elements and the sparse nature of thechannel complicates the use of digital beamforming.

Analog Beamforming: Analog beamforming overcomes limited number of RFchains issue by using analog phase shifters on each antenna element. Itis used in IEEE 802.11ad during the Sector Level Sweep (which identifiesthe best sector), Beam Refinement (which refines the sector to anantenna beam), and beam tracking (which adjusts the sub-beams over timeto account for any change in the channel) procedures. Analog beamformingis also used in IEEE 802.15.3. In this case a binary search beamtraining algorithm using a layered multi-resolution beamforming codebookis used. Analog beamforming is typically limited to single streamtransmission.

Hybrid beamforming: In hybrid beamforming, the precoder is dividedbetween analog and digital domains. Each domain has precoding andcombining matrices with different structural constraints, e.g., constantmodulus constraint for combining matrices in the analog domain. Thisdesign results in a compromise between hardware complexity and systemperformance. Hybrid beamforming may be able to achieve digital precodingperformance due to sparse nature of channel and supportmulti-user/multi-stream multiplexing. However, it is limited by numberof RF chains. This may not be an issue as mmWave channels are sparse inthe angular domain so this limitation may not be as important.

Multi-Antenna Analogue beamforming methods for 802.11ad+. Based onissues the analog beamforming found in IEEE 802.11ad, analog beamformingmethods for 802.11ad+/802.11ay have been proposed in U.S. Utility patentapplication Ser. No. 14/441,237, filed May 7, 2015, titled, BeamformingMethods and Procedures in mmW WLAN Systems. Disclosed embodimentsincluded the following:

-   -   Spatial diversity with beam switching.    -   Spatial diversity with a single beam.    -   Weighted multipath beamforming training.    -   Beam division multiple access.    -   Single user spatial multiplexing.    -   Reduced beamforming training overhead.

In the above disclosure, two architectures were proposed, the first withall physical antennas (PAs) excited by all the weights (shown in FIG. 9), while the second has different PAs excited by separate weights (shownin FIG. 10 ).

In various embodiments, the present disclosure relates to combinationsof analog and digital precoding (hybrid mmWave precoding) to enablemulti-stream/multi-user transmission.

SUMMARY

Systems and methods described herein are provided for multidimensionalbeam refinement procedures and signaling for millimeter wave WLANs.

BRP MAC Packet for M-Dimensional Transmission. The current BRP MAC in11ad is designed to setup, beam refinement and feedback for the singlebeam transmission that exists in 802.11ad. In FIG. 11 , a MAC packet1102 includes the BRP Request Field 1104 and the DMG Beam RefinementElement 1106. The supporting PHY layer PPDU used to estimate the bestbeam in a BRP procedure is designed for single beam transmission (asshown in FIG. 12 ). The elements of this PPDU include an AGC field, aChannel Estimation Field, and a TRN field for the single Tx-Rx antennapair and signal channel. For multi-dimensional BRP (where the dimensionsmay be multiple transmit-receive beam pairs, multiple polarizations ormultiple channels), methods to extend the MAC packet and the PPDU formatwith or without backwards compatibility are disclosed herein. Themultiple dimensions may be supported jointly or separately.

BRP MAC Packet Overhead. With the increase in the amount of data neededto be signaled in the BRP MAC packet due to an increase in the number ofantennas and beams for the M-dimensional transmissions described above,a more efficient BRP packet is set forth herein to reduce the overhead.

BRP IFS. In 802.11ad, the interframe spacing between a BRP frame and itsresponse is set to a value greater than or equal to the short interframespace (SIFS) and less than or equal to beam refinement protocolinter-frame space (BRPIFS) with the value of BRPIFS fixed. For improvedfeedback in view of the multi-dimensionality described above, there maybe multiple BRP frame exchanges for optimized operation. Methods toimprove the efficiency of the BRP operation and to enable the signalingof and/or reduction in the BRPIFS duration are disclosed herein.

BRP IFS and channel access. With the possibility of the interframespacing being set to BRPIFS=44 usec, STAs that are in sleep mode or thatmiss the TxOP reservation frame may assume that the channel isunoccupied and interrupt the TxOP. Embodiments are disclosed herein forallowing the IFS to be set to a specific value while allowing for delaysin processing.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,presented by way of example in conjunction with the accompanyingdrawings, wherein:

FIG. 1 illustrates exemplary PPDU formats in 802.11ad.

FIG. 2 illustrates an exemplary Control PHY transmission diagram in802.11ad.

FIG. 3 illustrates an exemplary Sector Level Sweep training procedure.

FIG. 4 illustrates an exemplary SSW frame format.

FIG. 5 illustrates an exemplary SSW field format.

FIG. 6A illustrates an exemplary SSW feedback field format whentransmitted as part of an ISS.

FIG. 6B illustrates an exemplary SSW feedback field format when nottransmitted as part of an ISS.

FIG. 7 illustrates an exemplary BRP TRN-RX packet.

FIG. 8 illustrates exemplary PPDU formats in 802.11ay.

FIG. 9 illustrates an exemplary architecture for beamforming where allphysical antennas are excited by all the weights.

FIG. 10 illustrates an exemplary architecture for beamforming wheredifferent physical antennas are excited by separate weights.

FIG. 11 illustrates an exemplary 802.11ad BRP MAC Packet for singlestream transmission.

FIG. 12 illustrates an exemplary 802.11ad BRP PPDU for single streamtransmission.

FIG. 13 illustrates an exemplary multiple antenna BRP with two beampairs for an exemplary initiator and responder.

FIG. 14 illustrates exemplary independent BRP request and DMG beamrefinement frames for each dimension using independent eBRP signaling.

FIG. 15 illustrates exemplary independent BRP request fields, as may beincorporated in the frames of FIG. 14 .

FIG. 16 illustrates one embodiment for CSD during simultaneous BRP,where AGC and TRN fields are circularly-shifted as blocks.

FIG. 17 illustrates one embodiment for CSD during simultaneous BRP,where individual AGC fields and TRN fields are circularly-shifted.

FIG. 18 illustrates one embodiment of a simultaneous BRP procedure.

FIG. 19 illustrates one embodiment of a joint BRP request field with afixed number of BRP requests.

FIG. 20 illustrates one embodiment of a joint BRP request field with adynamic number of BRP requests.

FIG. 21 illustrates one embodiment of an independent eDMG beamrefinement element.

FIG. 22 illustrates one embodiment of a joint eDMG beam refinementelement.

FIG. 23 illustrates an exemplary multi-dimensional eBRP procedure havingan eMIDC sub-phase for a multiple beam transmission.

FIG. 24 illustrates an exemplary multi-dimensional eBRP procedure havingan eBRP eMID sub-phase only for a multiple beam transmission.

FIG. 25 illustrates an exemplary R-eMID subphase of the multi-beam eBRP.

FIG. 26 illustrates an exemplary R-eBC subphase of the multi-beam eBRP.

FIG. 27 illustrates an exemplary minimum duration determinationprocedure at the receiver side.

FIG. 28 illustrates a first embodiment of an exemplary NDP BRP frameformat.

FIG. 29 illustrates a second embodiment of an exemplary NDP BRP frameformat.

FIG. 30A illustrates a baseline case in which interframe spacing canvary between a short interframe spacing (SIFS) and a beam refinementprotocol interframe spacing (BRPIFS).

FIGS. 30B-30C illustrate embodiments in which a response is availableand is transmitted with IFS equal to SIFS.

FIGS. 31A-31B illustrate embodiments in which a response is not readyfor transmission at the SIFS and the responder contends for the channel.

FIGS. 31C-31D illustrate embodiments in which a response is not readyfor transmission at the SIFS and the initiator polls for the response.

FIG. 31E illustrates an embodiment in which a response is not ready fortransmission at the SIFS and the responder occupies the channel untilthe response is sent.

FIG. 32A depicts an example communications system in which one or moredisclosed embodiments may be implemented.

FIG. 32B depicts an example wireless transmit/receive unit (WTRU) thatmay be used within the communications system of FIG. 32A.

FIG. 32C depicts an example radio access network (RAN) and an examplecore network that may be used within the communications system of FIG.32A.

FIG. 32D depicts a second example RAN and a second example core networkthat may be used within the communications system of FIG. 32A.

FIG. 32E depicts a third example RAN and a third example core networkthat may be used within the communications system of FIG. 32A.

FIG. 32F depicts an exemplary network entity that may be used within thecommunication system of FIG. 32A.

FIG. 33 is a graph illustrating the effect of SCblocks and IFS on theTxOP duration of a BRP procedure.

FIG. 34 illustrates an exemplary procedure and signaling for BRPfeedback without polling.

DETAILED DESCRIPTION

A detailed description of illustrative embodiments will now be providedwith reference to the various Figures. Although this descriptionprovides detailed examples of possible implementations, it should benoted that the provided details are intended to be by way of example andin no way limit the scope of the application.

Note that various hardware elements of one or more of the describedembodiments are referred to as “modules” that carry out (i.e., perform,execute, and the like) various functions that are described herein inconnection with the respective modules. As used herein, a moduleincludes hardware (e.g., one or more processors, one or moremicroprocessors, one or more microcontrollers, one or more microchips,one or more application-specific integrated circuits (ASICs), one ormore field programmable gate arrays (FPGAs), one or more memory devices)deemed suitable by those of skill in the relevant art for a givenimplementation. Each described module may also include instructionsexecutable for carrying out the one or more functions described as beingcarried out by the respective module, and it is noted that thoseinstructions could take the form of or include hardware (i.e.,hardwired) instructions, firmware instructions, software instructions,and/or the like, and may be stored in any suitable non-transitorycomputer-readable medium or media, such as commonly referred to as RAM,ROM, etc.

Network Architecture.

The systems and methods disclosed herein may be used with the wirelesscommunication systems described with respect to FIGS. 32A-32F. As aninitial matter, these wireless systems will be described. FIG. 32A is adiagram of an example communications system 100 in which one or moredisclosed embodiments may be implemented. The communications system 100may be a multiple access system that provides content, such as voice,data, video, messaging, broadcast, and the like, to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel-access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 32A, the communications system 100 may include WTRUs102 a, 102 b, 102 c, and/or 102 d (which generally or collectively maybe referred to as WTRU 102), a RAN 103/104/105, a core network106/107/109, a public switched telephone network (PSTN) 108, theInternet 110, and other networks 112, though it will be appreciated thatthe disclosed embodiments contemplate any number of WTRUs, basestations, networks, and/or network elements. Each of the WTRUs 102 a,102 b, 102 c, 102 d may be any type of device configured to operateand/or communicate in a wireless environment. By way of example, theWTRUs 102 a, 102 b, 102 c, 102 d may be configured to transmit and/orreceive wireless signals and may include user equipment (UE), a mobilestation, a fixed or mobile subscriber unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a smartphone, a laptop, anetbook, a personal computer, a wireless sensor, consumer electronics,and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106/107/109, theInternet 110, and/or the networks 112. By way of example, the basestations 114 a, 114 b may be a base transceiver station (BTS), a Node-B,an eNode B, a Home Node B, a Home eNode B, a site controller, an accesspoint (AP), a wireless router, and the like. While the base stations 114a, 114 b are each depicted as a single element, it will be appreciatedthat the base stations 114 a, 114 b may include any number ofinterconnected base stations and/or network elements.

The base station 114 a may be part of the RAN 103/104/105, which mayalso include other base stations and/or network elements (not shown),such as a base station controller (BSC), a radio network controller(RNC), relay nodes, and the like. The base station 114 a and/or the basestation 114 b may be configured to transmit and/or receive wirelesssignals within a particular geographic region, which may be referred toas a cell (not shown). The cell may further be divided into sectors. Forexample, the cell associated with the base station 114 a may be dividedinto three sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 115/116/117,which may be any suitable wireless communication link (e.g., radiofrequency (RF), microwave, infrared (IR), ultraviolet (UV), visiblelight, and the like). The air interface 115/116/117 may be establishedusing any suitable radio access technology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel-accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 103/104/105 and the WTRUs 102a, 102 b, 102 c may implement a radio technology such as UniversalMobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA),which may establish the air interface 115/116/117 using wideband CDMA(WCDMA). WCDMA may include communication protocols such as High-SpeedPacket Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may includeHigh-Speed Downlink Packet Access (HSDPA) and/or High-Speed UplinkPacket Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface115/116/117 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 32A may be a wireless router, Home NodeB, Home eNode B, or access point, as examples, and may utilize anysuitable RAT for facilitating wireless connectivity in a localized area,such as a place of business, a home, a vehicle, a campus, and the like.In one embodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, and the like) to establish a picocell or femtocell. As shown inFIG. 32A, the base station 114 b may have a direct connection to theInternet 110. Thus, the base station 114 b may not be required to accessthe Internet 110 via the core network 106/107/109.

The RAN 103/104/105 may be in communication with the core network106/107/109, which may be any type of network configured to providevoice, data, applications, and/or voice over internet protocol (VoIP)services to one or more of the WTRUs 102 a, 102 b, 102 c, 102 d. Asexamples, the core network 106/107/109 may provide call control, billingservices, mobile location-based services, pre-paid calling, Internetconnectivity, video distribution, and the like, and/or performhigh-level security functions, such as user authentication. Although notshown in FIG. 32A, it will be appreciated that the RAN 103/104/105and/or the core network 106/107/109 may be in direct or indirectcommunication with other RANs that employ the same RAT as the RAN103/104/105 or a different RAT. For example, in addition to beingconnected to the RAN 103/104/105, which may be utilizing an E-UTRA radiotechnology, the core network 106/107/109 may also be in communicationwith another RAN (not shown) employing a GSM radio technology.

The core network 106/107/109 may also serve as a gateway for the WTRUs102 a, 102 b, 102 c, 102 d to access the PSTN 108, the Internet 110,and/or other networks 112. The PSTN 108 may include circuit-switchedtelephone networks that provide plain old telephone service (POTS). TheInternet 110 may include a global system of interconnected computernetworks and devices that use common communication protocols, such asthe transmission control protocol (TCP), user datagram protocol (UDP)and IP in the TCP/IP Internet protocol suite. The networks 112 mayinclude wired and/or wireless communications networks owned and/oroperated by other service providers. For example, the networks 112 mayinclude another core network connected to one or more RANs, which mayemploy the same RAT as the RAN 103/104/105 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 32A may be configuredto communicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 32B is a system diagram of an example WTRU 102. As shown in FIG.32B, the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, a non-removable memory 130, a removable memory132, a power source 134, a global positioning system (GPS) chipset 136,and other peripherals 138. The transceiver 120 may be implemented as acomponent of decoder logic 119. For example, the transceiver 120 anddecoder logic 119 can be implemented on a single LTE or LTE-A chip. Thedecoder logic may include a processor operative to perform instructionsstored in a non-transitory computer-readable medium. As an alternative,or in addition, the decoder logic may be implemented using custom and/orprogrammable digital logic circuitry.

It will be appreciated that the WTRU 102 may include any sub-combinationof the foregoing elements while remaining consistent with an embodiment.Also, embodiments contemplate that the base stations 114 a and 114 b,and/or the nodes that base stations 114 a and 114 b may represent, suchas but not limited to transceiver station (BTS), a Node-B, a sitecontroller, an access point (AP), a home node-B, an evolved home node-B(eNodeB), a home evolved node-B (HeNB), a home evolved node-B gateway,and proxy nodes, among others, may include some or all of the elementsdepicted in FIG. 32B and described herein.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 32Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 115/116/117. For example, in one embodiment,the transmit/receive element 122 may be an antenna configured totransmit and/or receive RF signals. In another embodiment, thetransmit/receive element 122 may be an emitter/detector configured totransmit and/or receive IR, UV, or visible light signals, as examples.In yet another embodiment, the transmit/receive element 122 may beconfigured to transmit and receive both RF and light signals. It will beappreciated that the transmit/receive element 122 may be configured totransmit and/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 32B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 115/116/117.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, asexamples.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. As examples, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),and the like), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 115/116/117from a base station (e.g., base stations 114 a, 114 b) and/or determineits location based on the timing of the signals being received from twoor more nearby base stations. It will be appreciated that the WTRU 102may acquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 32C is a system diagram of the RAN 103 and the core network 106according to an embodiment. As noted above, the RAN 103 may employ aUTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102 cover the air interface 115. The RAN 103 may also be in communicationwith the core network 106. As shown in FIG. 32C, the RAN 103 may includeNode-Bs 140 a, 140 b, 140 c, which may each include one or moretransceivers for communicating with the WTRUs 102 a, 102 b, 102 c overthe air interface 115. The Node-Bs 140 a, 140 b, 140 c may each beassociated with a particular cell (not shown) within the RAN 103. TheRAN 103 may also include RNCs 142 a, 142 b. It will be appreciated thatthe RAN 103 may include any number of Node-Bs and RNCs while remainingconsistent with an embodiment.

As shown in FIG. 32C, the Node-Bs 140 a, 140 b may be in communicationwith the RNC 142 a. Additionally, the Node-B 140 c may be incommunication with the RNC 142 b. The Node-Bs 140 a, 140 b, 140 c maycommunicate with the respective RNCs 142 a, 142 b via an Iub interface.The RNCs 142 a, 142 b may be in communication with one another via anIur interface. Each of the RNCs 142 a, 142 b may be configured tocontrol the respective Node-Bs 140 a, 140 b, 140 c to which it isconnected. In addition, each of the RNCs 142 a, 142 b may be configuredto carry out or support other functionality, such as outer-loop powercontrol, load control, admission control, packet scheduling, handovercontrol, macrodiversity, security functions, data encryption, and thelike.

The core network 106 shown in FIG. 32C may include a media gateway (MGW)144, a mobile switching center (MSC) 146, a serving GPRS support node(SGSN) 148, and/or a gateway GPRS support node (GGSN) 150. While each ofthe foregoing elements are depicted as part of the core network 106, itwill be appreciated that any one of these elements may be owned and/oroperated by an entity other than the core network operator.

The RNC 142 a in the RAN 103 may be connected to the MSC 146 in the corenetwork 106 via an IuCS interface. The MSC 146 may be connected to theMGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional landline communications devices.

The RNC 142 a in the RAN 103 may also be connected to the SGSN 148 inthe core network 106 via an IuPS interface. The SGSN 148 may beconnected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between the WTRUs 102a, 102 b, 102 c and IP-enabled devices.

As noted above, the core network 106 may also be connected to thenetworks 112, which may include other wired and/or wireless networksthat are owned and/or operated by other service providers.

FIG. 32D is a system diagram of the RAN 104 and the core network 107according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 107.

The RAN 104 may include eNode Bs 160 a, 160 b, 160 c, though it will beappreciated that the RAN 104 may include any number of eNode Bs whileremaining consistent with an embodiment. The eNode Bs 160 a, 160 b, 160c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode Bs 160 a, 160 b, 160 c may implement MIMO technology. Thus,the eNode B 160 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode Bs 160 a, 160 b, 160 c may be associated with aparticular cell (not shown) and may be configured to handleradio-resource-management decisions, handover decisions, scheduling ofusers in the uplink and/or downlink, and the like. As shown in FIG. 32D,the eNode Bs 160 a, 160 b, 160 c may communicate with one another overan X2 interface.

The core network 107 shown in FIG. 32D may include a mobility managemententity (MME) 162, a serving gateway 164, and a packet data network (PDN)gateway 166. While each of the foregoing elements are depicted as partof the core network 107, it will be appreciated that any one of theseelements may be owned and/or operated by an entity other than the corenetwork operator.

The MME 162 may be connected to each of the eNode Bs 160 a, 160 b, 160 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 162 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 162 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 164 may be connected to each of the eNode Bs 160 a,160 b, 160 c in the RAN 104 via the S1 interface. The serving gateway164 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 164 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 164 may also be connected to the PDN gateway 166,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 107 may facilitate communications with other networks.For example, the core network 107 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional landline communications devices. For example, the corenetwork 107 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 107 and the PSTN 108. In addition, the corenetwork 107 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired and/or wireless networksthat are owned and/or operated by other service providers.

FIG. 32E is a system diagram of the RAN 105 and the core network 109according to an embodiment. The RAN 105 may be an access service network(ASN) that employs IEEE 802.16 radio technology to communicate with theWTRUs 102 a, 102 b, 102 c over the air interface 117. As will be furtherdiscussed below, the communication links between the differentfunctional entities of the WTRUs 102 a, 102 b, 102 c, the RAN 105, andthe core network 109 may be defined as reference points.

As shown in FIG. 32E, the RAN 105 may include base stations 180 a, 180b, 180 c, and an ASN gateway 182, though it will be appreciated that theRAN 105 may include any number of base stations and ASN gateways whileremaining consistent with an embodiment. The base stations 180 a, 180 b,180 c may each be associated with a particular cell (not shown) in theRAN 105 and may each include one or more transceivers for communicatingwith the WTRUs 102 a, 102 b, 102 c over the air interface 117. In oneembodiment, the base stations 180 a, 180 b, 180 c may implement MIMOtechnology. Thus, the base station 180 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 102 a. The base stations 180 a, 180 b, 180 c may alsoprovide mobility-management functions, such as handoff triggering,tunnel establishment, radio-resource management, traffic classification,quality-of-service (QoS) policy enforcement, and the like. The ASNgateway 182 may serve as a traffic aggregation point and may beresponsible for paging, caching of subscriber profiles, routing to thecore network 109, and the like.

The air interface 117 between the WTRUs 102 a, 102 b, 102 c and the RAN105 may be defined as an R1 reference point that implements the IEEE802.16 specification. In addition, each of the WTRUs 102 a, 102 b, 102 cmay establish a logical interface (not shown) with the core network 109.The logical interface between the WTRUs 102 a, 102 b, 102 c and the corenetwork 109 may be defined as an R2 reference point (not shown), whichmay be used for authentication, authorization, IP-host-configurationmanagement, and/or mobility management.

The communication link between each of the base stations 180 a, 180 b,180 c may be defined as an R8 reference point that includes protocolsfor facilitating WTRU handovers and the transfer of data between basestations. The communication link between the base stations 180 a, 180 b,180 c and the ASN gateway 182 may be defined as an R6 reference point.The R6 reference point may include protocols for facilitating mobilitymanagement based on mobility events associated with each of the WTRUs102 a, 102 b, 102 c.

As shown in FIG. 32E, the RAN 105 may be connected to the core network109. The communication link between the RAN 105 and the core network 109may defined as an R3 reference point that includes protocols forfacilitating data transfer and mobility-management capabilities, asexamples. The core network 109 may include a mobile-IP home agent(MIP-HA) 184, an authentication, authorization, accounting (AAA) server186, and a gateway 188. While each of the foregoing elements aredepicted as part of the core network 109, it will be appreciated thatany one of these elements may be owned and/or operated by an entityother than the core network operator.

The MIP-HA 184 may be responsible for IP-address management, and mayenable the WTRUs 102 a, 102 b, 102 c to roam between different ASNsand/or different core networks. The MIP-HA 184 may provide the WTRUs 102a, 102 b, 102 c with access to packet-switched networks, such as theInternet 110, to facilitate communications between the WTRUs 102 a, 102b, 102 c and IP-enabled devices. The AAA server 186 may be responsiblefor user authentication and for supporting user services. The gateway188 may facilitate interworking with other networks. For example, thegateway 188 may provide the WTRUs 102 a, 102 b, 102 c with access tocircuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionallandline communications devices. In addition, the gateway 188 mayprovide the WTRUs 102 a, 102 b, 102 c with access to the networks 112,which may include other wired and/or wireless networks that are ownedand/or operated by other service providers.

Although not shown in FIG. 32E, it will be appreciated that the RAN 105may be connected to other ASNs and the core network 109 may be connectedto other core networks. The communication link between the RAN 105 theother ASNs may be defined as an R4 reference point (not shown), whichmay include protocols for coordinating the mobility of the WTRUs 102 a,102 b, 102 c between the RAN 105 and the other ASNs. The communicationlink between the core network 109 and the other core networks may bedefined as an R5 reference point (not shown), which may includeprotocols for facilitating interworking between home core networks andvisited core networks.

FIG. 32F depicts an example network entity 190 that may be used withinthe communication system 100 of FIG. 32A. As depicted in FIG. 32F,network entity 190 includes a communication interface 192, a processor194, and non-transitory data storage 196, all of which arecommunicatively linked by a bus, network, or other communication path198.

Communication interface 192 may include one or more wired communicationinterfaces and/or one or more wireless-communication interfaces. Withrespect to wired communication, communication interface 192 may includeone or more interfaces such as Ethernet interfaces, as an example. Withrespect to wireless communication, communication interface 192 mayinclude components such as one or more antennae, one or moretransceivers/chipsets designed and configured for one or more types ofwireless (e.g., LTE) communication, and/or any other components deemedsuitable by those of skill in the relevant art. And further with respectto wireless communication, communication interface 192 may be equippedat a scale and with a configuration appropriate for acting on thenetwork side—as opposed to the client side—of wireless communications(e.g., LTE communications, Wi-Fi communications, and the like). Thus,communication interface 192 may include the appropriate equipment andcircuitry (perhaps including multiple transceivers) for serving multiplemobile stations, UEs, or other access terminals in a coverage area.

Processor 194 may include one or more processors of any type deemedsuitable by those of skill in the relevant art, some examples includinga general-purpose microprocessor and a dedicated DSP.

Data storage 196 may take the form of any non-transitorycomputer-readable medium or combination of such media, some examplesincluding flash memory, read-only memory (ROM), and random-access memory(RAM) to name but a few, as any one or more types of non-transitory datastorage deemed suitable by those of skill in the relevant art could beused. As depicted in FIG. 32F, data storage 196 contains programinstructions 197 executable by processor 194 for carrying out variouscombinations of the various network-entity functions described herein.

In some embodiments, the network-entity functions described herein arecarried out by a network entity having a structure similar to that ofnetwork entity 190 of FIG. 32F. In some embodiments, one or more of suchfunctions are carried out by a set of multiple network entities incombination, where each network entity has a structure similar to thatof network entity 190 of FIG. 32F. In various different embodiments,network entity 190 is—or at least includes—one or more of (one or moreentities in) RAN 103, (one or more entities in) RAN 104, (one or moreentities in) RAN 105, (one or more entities in) core network 106, (oneor more entities in) core network 107, (one or more entities in) corenetwork 109, base station 114 a, base station 114 b, Node-B 140 a,Node-B 140 b, Node-B 140 c, RNC 142 a, RNC 142 b, MGW 144, MSC 146, SGSN148, GGSN 150, eNode B 160 a, eNode B 160 b, eNode B 160 c, MME 162,serving gateway 164, PDN gateway 166, base station 180 a, base station180 b, base station 180 c, ASN gateway 182, MIP-HA 184, AAA 186, andgateway 188. And certainly other network entities and/or combinations ofnetwork entities could be used in various embodiments for carrying outthe network-entity functions described herein, as the foregoing list isprovided by way of example and not by way of limitation.

BRP MAC Packet for M-Dimensional Transmission.

The current BRP MAC in 11ad is designed to provide setup, beamrefinement and feedback for the single beam transmission that exists in802.11ad. The MAC packet includes the BRP Request Field and the DMG BeamRefinement Element (see FIG. 11 ). The supporting PHY layer PPDU used toestimate the best beam in a BRP procedure is designed for single beamtransmission (as shown in FIG. 12 ). The elements of this PPDU includean AGC field, a Channel Estimation Field and a TRN field for the singleTx-Rx antenna pair and signal channel. For multi-dimensional BRP (wherethe dimensions may be multiple transmit-receive beam pairs, multiplepolarizations, or multiple channels, and/or the like), set forth beloware methods to extend the MAC packet and the PPDU format with or withoutbackwards compatibility. The multiple dimensions may be supportedjointly or separately.

Methods and procedures are set forth in this section to address theseproblems, and others.

Multi-Dimensional Enhanced Beam Refinement Protocol MAC and PHY FrameDesign.

In some embodiments, the design of an Enhanced Beam Refinement Protocol(eBRP) MAC frame (and the associated PHY PPDU) is disclosed to supportmulti-dimensional BRP procedures. The multi-dimensional BRP proceduresmay be specified with respect to space, frequency, and/or polarization.

Capability Indication for Multi-Dimensional eBRP Procedure.

To enable negotiation of the eDMG STA capability during the eBRP setupphase, eDMG capability fields are defined that provide indications ofthe following transmission dimensions:

-   -   1) the allowed number of transmit-receive beam pairs,    -   2) the number of channels that can be aggregated or bonded,        and/or    -   3) the maximum number of spatial streams.

This allows the eDMG STA to negotiate these parameters or dimensions tobe used with another STA during the eBRP setup procedure. The number oftransmit/receive beam pairs can be greater than the number of streamsallowed, e.g., N_beams=4 and Nss=2. The last negotiated parameters usedin sector level sweep procedures may include the number of beam-pairsand the number of streams.

BRP Procedure and Signaling for Multi-Dimensional Transmission.

FIG. 13 shows an exemplary initiator 1302 and responder 1304 with twobeam pairs. Beam pair 1 is found based on a sweep in the upper sectorswhile beam pair 2 is found based on a sweep of the lower sectors. Assuch, information on the specific beam pair that is being refined may besignaled in an updated eBRP packet.

The eBRP refinement procedure may be signaled and/or executedindependently or jointly per dimension. In various embodiments, the eBRPrefinement signaling may be coded or transmitted independently perdimension. This signaling may occur in the setup phase or during therefinement procedure. In various embodiments, the eBRP refinementprocedure may be performed independently per dimension. In variousembodiments, the eBRP refinement signaling may be coded or transmittedjointly per dimension. In various embodiments, the eBRP refinementprocedure may be performed jointly per dimension.

Procedures to identify the quality of each dimension (e.g.,transmit/receive beam-pair or channel) may be used as input to decide(a) which dimensions are to be updated and (b) whether the dimensionsare to be signaled and/or executed independently or jointly.

In mmWave beamforming for single stream WLANs as implemented in802.11ad, the transmit-receive pair may go through the followingprocedures:

-   -   Sector Level Sweep (SLS): Identifies the large sectors and        enables communication between Tx and Rx at DMG control mode rate        or higher.    -   Beam Refinement Protocol (BRP): enables receive training and        enables iterative refinement of the AWV of both transmitter and        receiver at both participating STAs.

The BRP is composed of one or more of the following: a BRP setup,Multiple Sector Identification Detection (MID), Beam Combining (BC),Multiple Sector Identification and Capture (MIDC), Beam RefinementTransaction, and/or the like.

A BRP setup serves to exchange BRP parameters between the initiator andresponder. This step is used only when BRP does not immediately follow aSLS.

In MID, a quasi-omni transmit pattern is tested against a number ofAntenna Waveform Vectors (AWVs) and identifies the best set of receiveantennas for the initiator (I-MID) or responder (R-MID). A quasi-omnipattern is the pattern closest to omni-directional that is available atan eDMG antenna. It may be made up of multiple beams and isnon-directional.

BC comprises an exhaustive pairwise test of a set of transmit andreceive AWVs.

MIDC combines the MID and BC procedures.

A Beam Refinement Transaction is a set of BRP frames that is composed onrequest for and responses to AWV tests by the initiator or responder.

For multiple dimensional transmission, one or more of the followingmodifications disclosed below may be used.

Enhanced Sector Level Sweep (eSLS) may be used to identify the largesectors for each dimension and enables communication between Tx and Rxat eDMG control mode rate or higher. For multiple beam transmission, aneSLS may be used to create multiple Tx/Rx beams. The dimensions may beseparated by any of the following: time, eDMG antenna, polarization,frequency, etc. To improve the reliability of the eDMG control modetransmission, the following may be used:

-   -   A beam selection algorithm that selects the beam with the best        quality (e.g., the largest SNR) to transmit the control        information and improve the reliability of the control mode.    -   A beam diversity code (such as an Alamouti-like code, e.g., STBC        or SFBC) to transmit the control information and improve the        reliability of the eDMG control mode.        -   Note that for an eDMG Beam Refinement element, if the            element is transmitted during a request or negotiation            (capability request=1), the transmission may be in diversity            mode. In other modes, the transmission may be in diversity,            quasi-omni or beam-based mode.

An Enhanced Beam Refinement Protocol (eBRP) may be utilized to enablereceive training for each beam in each dimension, while also enablingiterative refinement of the Antenna Weight Vectors (AWVs) of all thebeams of both transmitter and receiver at both participating STAs.

In single beam MID, the requestor feeds back SNR and sector IDs of thelast SLS phase to enable the initiator to identify the AWVs that areselected. For multi-dimensional transmission (e.g., multipletransmit-receive beam or multiple channel transmission), thisinformation may be signaled in a dimension specific manner.

In various embodiments, the eBRP procedure may be executed independentlyfor each beam pair or may be executed jointly among all (or a subset) ofbeam pairs.

In embodiments having independent eBRP procedure execution, eachdimension (e.g., a transmit-receive beam pair) performs the eBRPprocedure as a separate procedure. This is a simple backwards compatibleextension of the current 802.11ad procedure with additional signalingindicating the desired beam pair or dimension.

In independent eBRP signaling, each dimension (e.g., a transmit-receivebeam pair) has its own independent signaling as illustrated in FIG. 14 .Each dimension (e.g., a transmit-receive pair) may have its ownindependent BRP Request Field 1402 and DMG Beam Refinement element 1404to enable feedback of the BS-FBCK field (the index of the TRN-T fieldthat was received with the best quality in the last received BRP-TX).This is a backwards compatible extension of the current 802.11 adprocedure.

In one example, the additional dimensional signaling (which without lossof generality may be labelled as the Tx-Rx Beam ID), may be placed inthe BRP Request field. In this case, the reserved bits (B27 to B31) inthe existing BRP request field format may be used (see 1502 in FIG. 15). The frames may be transmitted sequentially. In scenarios where theremay be multiple existing dimensions already available to transmitinformation, they may be transmitted independently on a per dimensionbasis (e.g., in the case of multiple transmit-receive beam pairs), whereeach dimension may transmit its information on its own beam.

In embodiments having joint/simultaneous eBRP procedure execution,multiple dimensions (e.g., multiple transmit-receive beam pairs) mayperform the eBRP procedure simultaneously. The eBRP procedure can beimplemented in a number of ways. For example, in one embodiment it maybe based on an exhaustive search of all possible beam pairs. In anotherembodiment, it may be based on a search of the next best beam pairconditioned on the selection of the previously selected best beam pairs.

In another embodiment, the eBRP procedure may be based on a simultaneoussearch of all possible beam pairs. In this case, the 802.11ad BRP PPDUmay be modified to support the simultaneous transmission of the CE, AGC1802, and TRN-T/R 1804 signals as shown in FIG. 18 , and discussed inU.S. Provisional Application for Patent Ser. No. 61/365,014, filed Jul.21, 2016, which is incorporated herein by reference in its entirety.

The CEF may by orthogonalized by sending orthogonal (using conjugationfor example) or by masking the sequences from each spatial stream withan orthogonal matrix. The AGC may be sent on multiple streams usingmultiple techniques, e.g., using cyclic shift diversity (CSD), todecrease the correlation between the streams and allow the receiver toset the AGC settings properly during the simultaneous BRP. In variousembodiments, CSD during the simultaneous BRP may follow twoapproaches: 1) the AGC fields 1602 and TRN fields 1604 arecircularly-shifted as blocks as shown in FIG. 16 ; or 2) individual AGCfields 1702 and TRN fields 1704 are circularly-shifted as shown in FIG.17 . In 2), the sequences in AGC fields and TRN fields may be differenton each time slot. CSD may also be applied to EDMG CEF field. In thiscase, the block-circular shift for TRN fields in 1) and 2) may alsoinclude EDMG CEF. The TRN-T/R sequences may be orthogonalized by sendingorthogonal (using conjugation for example) or by masking the sequencesfrom each spatial stream with an orthogonal matrix. Signaling toindicate the number of simultaneous streams is needed. This may besignaled in the BRP frame (in the MAC) or signaled implicitly by theAGC.

In embodiments having joint/simultaneous BRP signaling, each dimension(e.g., each transmit-receive pair) is assigned a BRP request field wherethe fields may be concatenated in a fixed or dynamic manner.

In embodiments having fixed concatenation, the number of BRP requestfields are fixed based on the maximum number of transmit receive beamsor dimensions required. In the case that a transmit receive beam doesnot need refinement, the MID-REQ, BC-REQ, MID-Grant, and BC-Grant fieldsmay be set to zero (see FIG. 19 ). The number of dimensions tosimultaneously refine (and the possible grouping) may also be signaled.In one method, the number of dimensions to be simultaneously processedmay be agreed on during the BRP setup phase. In one method, the numberof dimensions to be simultaneously processed may be explicitly signaledin the PHY header or MAC frame, e.g., BRP request field. In one method,the grouping of dimensions may be decided implicitly by the arrangementof the BRP request fields. In one method, the grouping may be decided byexplicit signaling in the PHY header or MAC frame, e.g., the BRP requestfields.

In embodiments having dynamic concatenation, the number of eBRP requestfields are changed based on the number of transmit receive beams thatmay need refinement. A parameter that indicates the number of eBRPrequests maybe placed in the BRP frame (for example in the PHY or MACheader) or somewhere in the MAC frame. The number of BRP requests mayalso be derived implicitly from the length of the BRP frame. This isillustrated in a BRP frame 2000 in FIG. 20 .

For joint eBRP procedure execution, the eDMG Beam Refinement element maybe modified to allow for feedback of the desired number of BS-FBCK andBS-FBCK Antenna ID fields. An additional field indicating thecorresponding dimension (e.g., a transmit-receive beam pair) may also beneeded for some embodiments. In one method, each transmit-receive beampair may feed back an independent element (see 2100 in FIG. 21 ).

This may result in unnecessary overhead due to the commonality of someof the parameters. In another method, a signal eDMG Beam Refinementelement may be sent with multiple BS-FBCK, BS-FBCK Antenna ID, anddimension (e.g., transmit-receive beam) fields (see 2200 in FIG. 22 ).In the BRP procedure, the transmitter/receiver may in some embodimentsneed to obtain the IDs and SNRs of the Tx sectors received during theSLS phase for the use of the L-RX field in the BRP sub-phases. In theeBRP procedure, the feedback may be identified based on thetransmitter-receiver beam pair.

If detailed channel measurement feedback is desired, then the detailedmeasurement may also be per dimension. Alternatively, the detailedchannel measurement feedback may be a composite of all the differentdimensions, e.g., an effective MIMO channel.

In this case, a simple extension of the 802.11ad BRP feedback may beused in which each channel tap is reported as an Nr×Nt×x-bits with thein-phase and quadrature component pairs of the responses estimatedrelative to the amplitude of the strongest I/Q element measured witheach component value represented as a two's complement number. Anexemplary multi-dimensional eBRP procedure 2300 illustrating an eMIDCsub-phase for a multiple beam transmission is shown in FIG. 23 with FIG.25 and FIG. 26 illustrating the R-eMID and R-eBC subphases 2500 and2600, respectively, of the multi-beam eBRP. In this example, thedimensions are transmit receive beam pairs.

An exemplary multi-dimensional eBRP procedure 2400 illustrating an eBRPeMID sub-phase only for a multiple beam transmission is shown in FIG. 24. In that example, the dimensions are transmit receive beam pairs.

As further examples, a method may include conducting an enhanced beamrefinement protocol (eBRP) between an initiator device and at least oneresponder device for at least one transmit-receive beam pair, where theat least one transmit-receive beam pair has a plurality of dimensions.

The eBRP may include receive training for each of the at least one beampair and enables iterative refinement of antenna weight vectors (AWVs)of all beams of both transmitter and receiver at the initiator deviceand the at least one responder device.

The AWVs may be identified in a dimension specific manner.

The eBRP procedure may be conducted independently for each of the atleast one beam pairs.

Each of the at least one beam pairs may perform the eBRP procedure as aseparate procedure.

Each dimension of the at least one transmit-receive beam pair mayinclude its own independent BRP Request Field and DMG Beam Refinementelement to enable feedback of a BS-FBCK field.

The eBRP may be backward compatible with 802.11ad and, and may signaldimension identification information in the BRP request field.

Each of the at least one beam pairs may transmit its information on itsown beam.

The eBRP procedure may be conducted jointly among all of the at leastone beam pairs.

The eBRP procedure may be based on an exhaustive search of all possiblebeam pairs.

The eBRP procedure may be based on a search of a next best beam pairconditioned on selection of a previously selected best beam pair.

The eBRP procedure may be based on a simultaneous search of all possiblebeam pairs.

The BRP PPDU may be modified to support simultaneous transmission of CE,AGC, and TRN-T/R signals.

CEF may be orthogonalized by sending orthogonal or masking sequencesfrom each spatial stream with an orthogonal matrix.

The AGC may be sent using cyclic shift diversity.

AGC and TRN fields may be circularly shifted as blocks.

Individual AGC fields and TRN fields may be circularly shifted.

Cyclic shift diversity may be applied to the EDMG CEF field.

TRN-T/R sequences may be orthogonalized by sending orthogonal or maskingsequences from each spatial stream with an orthogonal matrix.

The number of simultaneous streams may be signaled in the BRP frame.

The number of simultaneous streams may be signaled implicitly by theAGC.

Each dimension may be assigned a BRP request field with the fieldsconcatenated in a fixed concatenation.

The number of BRP request fields may be fixed based on a maximum numberof dimensions required.

Each dimension may be assigned a BRP request field with the fieldsconcatenated in a dynamic concatenation.

The number of eBRP request fields may change based on the number oftransmit receive beams requesting refinement.

A parameter indicating the number of eBRP requests may be placed in theBRP frame.

A parameter indicating the number of eBRP requests may be placed in theMAC frame.

The number of BRP requests may be derived implicitly from a length ofthe BRP frame.

An eDMG beam refinement element may be modified to permit feedback of adesired number of BS-FBCK and BS-FBCk Antenna ID fields.

An additional field may be provided to indicate a correspondingdimension.

Each of the at least one beam pair may feed back an independent element.

A single eDMG beam refinement element may be sent with multiple BS-FBCK,BS-FBCK Antenna ID, and dimension fields.

The eBRP procedure may be conducted jointly for at least a subset of theat least one beam pairs.

In another example, a method includes: conducting an enhanced beamrefinement protocol (eBRP) between an initiator device and at least oneresponder device for at least two transmit-receive beam pairs, the atleast two transmit-receive beam pairs each having at least onedimension. The eBRP may include receive training for each of the atleast two beam pairs and enables iterative refinement of antenna weightvectors (AWVs) of all beams of both transmitter and receiver at theinitiator device and the at least one responder device.

Another example is a system that includes a processor and anon-transitory storage medium storing instructions operative, whenexecuted on the processor, to perform functions including conducting anenhanced beam refinement protocol (eBRP) between an initiator device andat least one responder device for at least one transmit-receive beampair, the at least one transmit-receive beam pair having a plurality ofdimensions.

Another example is a system that includes a processor and anon-transitory storage medium storing instructions operative, whenexecuted on the processor, to perform functions including: conducting anenhanced beam refinement protocol (eBRP) between an initiator device andat least one responder device for at least two transmit-receive beampairs, the at least two transmit-receive beam pairs each having at leastone dimension.

Short BRP Frame

BRP MAC Packet Overhead

With the increase in the amount of data to be signaled in the BRP MACpacket due to an increase in the number of antennas and beams for theM-dimensional transmissions described above, a more efficient BRP packetis set forth herein to reduce the overhead. Embodiments set forth belowrelate to reducing the size of the BRP frame to increase the efficiencyof the BRP procedure, in view of the multi-dimensionality describedabove.

Training Type Dependent BRP Minimum Duration Selection Procedure

In some embodiments, the minimum duration of data field of a BRP packetmay be varied depending on the purpose of the BRP training. For example,multiple BRP Minimum Durations may be defined. When certain conditionshave been met, a particular BRP Minimum Duration of the multipleavailable may be chosen.

In one example, two BRP Minimum Durations may be defined for differentBRP frames. BRP Minimum Duration 1 (short duration) may be used for:BRP-TX packet; BRP-RX packet where the receiver training request may besent in previous frame exchange; and/or BRP packet which may carry BRPMAC frame but no TRN field appended. BRP Minimum Duration 2 (longduration) may be used for BRP-RX packet where the receiver trainingrequest may be sent in MAC body of current frame.

Here, BRP-RX packet may refer to a packet with TRN-R training fieldappended which enable receiver antenna weight vector training. BRP-TXpacket may refer to a packet with TRN-T training field appended whichenable transmitter antenna weight vector training.

In another example, two BRP Minimum Durations may be defined for BRP-RXand BRP-TX packets respectively.

BRP Minimum Durations may be a set of values greater than or equal to 0.The shortest BRP Minimum Duration may be set to 0.

An exemplary transmitter procedure may be as given below.

-   -   1) The transmitter may acquire the media through contention or        scheduling. It may prepare a BRP packet transmission    -   2) According to the type of the BRP training packet, or the        usage of the BRP frame, or other criteria, the transmitter may        choose a particular BRP Minimum Duration.    -   3) The transmitter may implicitly or explicitly signal the        choice of the BRP Minimum Duration in PLCP Header and/or MAC        Header and/or MAC frame body. In the case of implicit signaling,        the signal may be the type of the BRP training packet, or the        usage of the BRP frame or other type of criteria by which the        transmitter and receiver may determine a particular BRP Minimum        Duration.    -   4) The transmitter may prepare the PPDU for the BRP packet. If        needed, the data field of the packet may be extended by extra        zero padding to meet the BRP Minimum Duration requirement.

An exemplary receiver procedure may be as given below (also shown asmethod 2700 in FIG. 27 ):

-   -   1) At 2702, the receiver may detect a packet.    -   2) AT 2704, by reading the PLCP header and/or MAC header and/or        MAC frame body, the receiver may notice this is a BRP packet.    -   3) At 2706, according to the explicit or implicit signaling, the        receiver may determine a particular BRP Minimum Duration used        for this packet.    -   4) At 2712, the receiver may perform data detection using the        BRP Minimum Duration determined at 2706 (e.g., BRPmin1 at 2708        or BRPmin2 at 2710).

Generalized Training Type Dependent BRP Minimum Duration SelectionProcedure

The above mentioned methods and procedures may be extended to a generalcase. In one such embodiment, a set of BRP Minimum Durations may bepre-defined or pre-determined. In one example, the set of BRP MinimumDurations may be discrete integer numbers between 0 and aBRPminLimit.For example, the aBRPminLimit may be set to a value 18 in unit of SCblocks or OFDM symbols. The set of BRP Minimum Duration may be definedas {6, 12, 18} in unit of SC blocks or OFDM symbols. Alternatively, theset of BRP Minimum Duration may have finer granularity, such as {0, 1,2, . . . , 18}. STAs including PCP/AP STAs and non-PCP/AP STAs maynegotiate the use of a BRP Minimum Duration. The STA capability ofsupporting a set or a subset of the pre-defined or pre-determined BRPMinimum Durations may be exchanged through Association Request/Response,Re-association Request/Response, Probe Request/Response, Beacon frames,or other type of management frames. The negotiation may be explicitlyperformed through packet exchanges between STAs.

FIG. 33 is a graph 3300 illustrating the effect of SCblocks and IFS onthe TxOP duration of a BRP procedure.

In one example, the duration negotiation may be initiated by a PCP/AP asfollows. A PCP/AP may transmit a BRP Minimum Duration request frame,which may request a STA to report the preferred BRP Minimum Duration.The STA addressed by the BRP Minimum Duration request frame may thensend a BRP Minimum Duration response/report frame, which may indicatethe preferred BRP Minimum Duration used by the STA. Optionally, thePCP/AP may confirm the BRP Minimum Duration for the STA. Afternegotiation, the BRP Minimum Duration may be used by the PCP/AP and STA,until it is updated through another BRP Minimum Durationrequest/response frame exchange.

In a second example, the duration negotiation may be initiated by a nonPCP/AP STA using a method such as the following. A non PCP/AP STA maytransmit a BRP Minimum Duration request frame, which may ask a PCP/APSTA to select or adjust BRP Minimum Duration for the STA. In this frame,one or more BRP Minimum Durations supported by the STA may be included.Alternatively, a minimum number of supported BRP Minimum Durations maybe included. The PCP/AP STA addressed by the BRP Minimum Durationrequest frame may then send a BRP Minimum Duration response/reportframe, which may indicate a BRP Minimum Duration for the STA. Afternegotiation, the BRP Minimum Duration may be used by the PCP/AP and STA,until it is updated through another BRP Minimum Durationrequest/response frame exchange.

In a third example, a PCP/AP may acquire the BRP Minimum Duration foreach associated STA through STA capability exchanges. Then the PCP/APmay determine the BRP Minimum Duration for each STA.

In an exemplary procedure for BRP Minimum Duration selection in DLMU-MIMO BRP training, a PCP/AP may use DL MU-MIMO like scheme to traintwo or more STAs concurrently using the entire bandwidth. In such anembodiment, the PCP/AP may check the BRP Minimum Durations for all thepotential receive STAs, and use the maximum value among them to set asthe BRP Minimum Duration for the DL MU-MIMO transmission.

In some embodiments, procedures are provided for MCS selection due toBRP Minimum Duration. Due to the BRP Minimum Duration requirement, aguaranteed number of resources may be required for the MAC bodytransmission. Thus, a MCS may be selected to fully use those resources.

Null Data Packet BRP Frame.

In 802.11, Null Data Packet (NDP) may refer to a PPDU which containsPLCP header but no MAC packet. The Signaling field in PLCP header may beoverwritten to carry BRP information. In general, one reserved bit inthe PLCP header, including legacy Header field and/or enhanced Headerfield, may indicate this is a NDP MAC frame, and the rest of bits in thefield may be overwritten. A field in the overwritten DNP MAC frame maybe used to indicate the MAC frame type. For example, it may indicatethis may be a NDP BRP frame.

In one method, a unified NDP BRP frame may be defined to carryinformation for simplified BRP frame exchanges.

In another method, a set of NDP BRP frames may be defined for differentpurpose. In this way, each NDP BRP frame may need to carry limitedinformation. For example, the NDP BRP frames may include but are notlimited to the following:

-   -   NDP BRP receiver training request frame    -   NDP BRP receiver training response frame    -   NDP BRP MIMO training request frame    -   NDP BRP MIMO training response frame    -   NDP BRP Setup frame    -   NDP BRP MID frame    -   NDP BRP BC frame

A NDP BRP frame 2800 may be defined as shown in FIG. 28 . With thisexemplary design, legacy fields, including L-STF, L-CEF and L-Headerfields may be the same as defined in 802.11ad. Fields in L-Header mayindicate the presence and length of TRN field. Enhanced Header A fieldmay be overwritten to carry BRP information. Enhanced STF and CEF fieldmay be optional. TRN field may be used for BRP training, which maysupport MIMO and multi-channel transmission.

Another NDP BRP frame 2900 may be defined as shown in FIG. 29 . Withthis exemplary design, multi-user BRP training may be performed. Legacyfields, including L-STF, L-CEF and L-Header may be the same as definedin 802.11ad. Fields in L-Header may indicate the presence and length ofTRN field. Enhanced Header A field may be overwritten to carry commonBRP information. Enhanced STF and CEF field may be used for MU AGC andchannel estimation. Enhanced Header B field may be overwritten to carryuser specific BRP information. TRN field may be used for BRP training,which may support MIMO and multi-channel transmission.

As further examples, a method may include acquiring media at atransmitter; preparing a BRP packet transmission from the transmitter;selecting, at the transmitter, a particular BRP minimum duration from aset of at least two BRP minimum durations; signaling the choice of theBRP minimum duration; preparing a PPDU for the BRP packet; andtransmitting the prepared BRP packet transmission from the transmitterto at least one receiver.

The particular BRP minimum duration may be selected based at least inpart on a type of a BRP training packet.

The particular BRP minimum duration may be selected based at least inpart on a usage of the BRP frame.

The choice of the BRP minimum duration may be explicitly signaled in oneof a PLCP header, a MAC header, or a MAC frame body.

The choice of the BRP minimum duration may be implicitly signaled basedat least in part on one of a type of the BRP training packet or a usageof the BRP frame.

Detecting a packet transmission at a receiver; determining that thedetected packet is a BRP packet; determining a particular BRP minimumduration, from a set of at least two BRP minimum durations, used for thedetected BRP packet; and performing data detection at the receiver usingthe determined BRP minimum duration.

The determining that the detected packet is a BRP packet may includereading at least one of a PLCP header, a MAC header, or a MAC framebody.

The determining the particular BRP minimum duration may be based atleast in part on implicit signaling.

The determining the particular BRP minimum duration may be based atleast in part on explicit signaling.

As another example, a method may in utilizing null data packets tooverwrite PLCP header information to carry BRP information.

A unified NDP BRP frame may be defined to carry information forsimplified BRP frame exchanges.

A set of NDP BRP frames may be defined for different purposes.

The set of NDP BRP frames may include: an NDP BRP receiver trainingrequest frame; an NDP BRP receiver training response frame; an NDP BRPMIMO training request frame; an NDP BRP MIMO training response frame; anNDP BRP Setup frame; an NDP BRP MID frame; and an NDP BRP BC frame.

An enhanced header A field may be overwritten to carry common BRPinformation, and an enhanced header B field may be overwritten to carryuser specific BRP information.

Another example is a system that includes a processor and anon-transitory storage medium storing instructions operative, whenexecuted on the processor, to perform functions including: acquiringmedia at a transmitter; preparing a BRP packet transmission from thetransmitter; selecting, at the transmitter, a particular BRP minimumduration from a set of at least two BRP minimum durations; signaling thechoice of the BRP minimum duration; preparing a PPDU for the BRP packet;and transmitting the prepared BRP packet transmission from thetransmitter to at least one receiver.

Another example is a system that includes a processor and anon-transitory storage medium storing instructions operative, whenexecuted on the processor, to perform functions including: detecting apacket transmission at a receiver; determining that the detected packetis a BRP packet; determining a particular BRP minimum duration, from aset of at least two BRP minimum durations, used for the detected BRPpacket; and performing data detection at the receiver using thedetermined BRP minimum duration.

Another example is a method that includes, at a STA: receiving a BRPminimum duration request from an AP; responding to the request byidentifying a preferred BRP minimum duration; and conducting beamrefinement with the AP using the identified BRP minimum duration.

Another example is a method that includes, at an AP: sending a BRPminimum duration request to a STA; receiving a response to the requestidentifying a preferred BRP minimum duration; and conducting beamrefinement with the STA using the identified BRP minimum duration.

Another example is a method performed by a non-PCP/AP requesting STA,where the method includes: transmitting to a responding STA a BRPminimum duration request identifying at least one BRP minimum durationsupported by the requesting STA; receiving from the responding STA aresponse indicating a BRP minimum duration; and conducting beamrefinement with the using the identified BRP minimum duration.

Another example is a method performed by an AP, where the methodincludes: communicating with a plurality of STAs to obtain a respectiveBRP minimum duration for each of the STAs; selecting a maximum valueamong the obtained BRP minimum durations; and using the selected maximumvalue among them as the BRP minimum duration for DL MU-MIMO transmissionto the STAs.

BRP InterFrame Spacing Negotiation

BRP IFS. For improved feedback in view of the multi-dimensionalitydescribed above, some embodiments make use of multiple BRP frameexchanges for optimized operation. Methods to improve the efficiency ofthe BRP operation and to enable the signaling of and/or reduction in theBRPIFS duration are set forth below.

In some embodiments, the maximum duration of the interframe spacingbetween BPR packets may be varied depending on the efficiency of theimplementation. In some embodiments, the IFS spacing may be quantized toone of a set of possible IFS spacing lengths.

Signaling may be added to enable the transmitter and receiver negotiatethe values used for the beam based interframe spacing parameters such asone or more of the following:

-   -   SBIFS: short Beamforming Interframe Spacing    -   BRPIFS: Beam Refinement Protocol Interframe Spacing    -   MBIFS: Medium Beamforming Interframe Spacing    -   LBIFS: Long Beamforming Interframe Spacing

When certain conditions have been met, a particular IFS spacing may bechosen.

In one embodiment, the IFS is dynamically selected from any value (i.e.unquantized). In this case, the AP and STA may signal the actual IFSvalue to be used to the network to enable STAs identify the actual IFSvalue to use.

In an exemplary embodiment, the AP and STA may assign a specific IFS toa specific BRP scenario. The scenario may be a function of one of thefollowing:

-   -   The type of feedback used, e.g. SNR only feedback vs        SNR+relative channel estimates feedback.    -   The antenna architecture, e.g. the IFS used may be different in        cases where the beam switch requires a switch between beams of        the same DMG antenna vs. a switch between different DMG        antennas. Note that the actual value may be negotiated and        signaled during the DMG setup procedure e.g. L_rx=10,        L_rx_dmg=1,2, etc.

If STA fails to feedback information within the requested timing, the APmay override the requested IFS time by bumping STA IFS up to next IFSduration in the case of quantized IFS space or by adding a predeterminedvalue to IFS value for the system.

In this case, the AP may need to signal the change in IFS value.

In one embodiment, the IFS used may be set based on a reference scenario(or set of reference scenarios). In this case, the Tx/Rx pair switch tothe reference scenario, measure the IFS and use the IFS in the BRPtransmission procedure.

An example of a scenario may be based on the following:

-   -   A specific initiator/responder reference configuration e.g. the        receive beams are set within a specific DMG antenna only.    -   The specific type of feedback e.g. SNR only feedback.    -   A time interval e.g. the time interval between reception of the        BRP measurement frame and transmission of the response or the        receive beams can be switched between each other within a        specified number of microseconds.

Note that the AP and STA(s) may negotiate parameters for each referencescenario.

In an exemplary embodiment, an IFS negotiation procedure operates asfollows. An AP sends an IFS measurement setup frame to one or more STAs.The AP may specify a specific configuration or scenario for themeasurement. The AP may indicate that the measurement is for one or morespecific STAs. Alternatively, the AP may assume that all STAs in PBSSwill be measured. The AP sends out a channel measurement frame to theSTA(s).

The STAs receive the measurement frame and estimate the duration of IFSneeded for transmission. The STAs feed back the IFS measurements to theAP. In one embodiment, the AP solicits the information, e.g. the STA(s)may be polled by the AP for the information. In another embodiment, theSTA(s) may pro-actively send the information to the AP e.g. bycontending for the channel.

The AP starts a BRP procedure. The AP sends a BRP frame with the IFSvalue to be used in the BRP setup frame. This allows all other STAs inthe network to know the IFS value to be used. STA processes informationand feeds back information with the desired IFS between frames. In oneembodiment, the STA may start sending information any time between SIFSand the IFS value set.

If the STA fails to reply with the IFS set, the AP may increase the IFSestimate for the desired scenario.

802.11ay BRP with SIFS Only.

The IFS may vary between SIFS and BRPIFS, as illustrated at 3002 in FIG.30A. With the possibility of the interframe spacing being set toBRPIFS=44 usec, STAs that are in sleep mode or that miss the TxOPreservation frame may assume that the channel is unoccupied and mayinterrupt the TxOP. To address this issue, the interframe spacing forthe BRP may be set to SIFS. However, feedback that needs additionalprocessing time that is greater than a SIFS may benefit from anefficient way to access the network. To enable this one of the followingmethods may be used.

If the response is available within SIFS of the reception BRPmeasurement frame, the response may be transmitted. Such an embodimentis illustrated in FIGS. 30B (IFS 3004) and 30C (IFS 3006).

If the response is not available within SIFS of the reception of the BRPmeasurement frame, one or more of the following methods may be employed.

In one method, an ACK may be transmitted by the responder, and it is theresponder's responsibility to access the channel to feed back therequired information. This may be done by (a) contending for thechannel, (b) sending a traffic available frame to the initiator torequest for channel access or (c) waiting for the initiator to poll itfor feedback. This method is illustrated in FIGS. 31A and 31B, whichillustrate IFS 3102 and 3104, respectively.

In another method, an ACK may be transmitted by the responder with theminimum time needed for access. The initiator may request theinformation (e.g. by polling) at a time interval greater than the timeindicated in the ACK. Note that this may be an absolute time interval ormay be a value indicating a quantized time interval. This method isillustrated in FIGS. 31C and 31D, which illustrate IFS 3106 and 3108,respectively.

In a further method, the responder may transmit dummy information in theinterval before information is ready to be transmitted. In one example,the responder may transmit repeated STF and/or LTF sequences for theduration of the wait interval. This method is illustrated in FIG. 31E,which illustrates IFS 3110.

Minimum Duration and IFS Negotiation.

Minimum Duration (aBRPminSCblocks) Negotiation

In an exemplary embodiment, an 11ay BRP protocol allows negotiation ofthe value of aBRPminSCblocks<=18. Minimum duration negotiation calls forselection and signaling of the aBRPminSCblocks values. In an embodiment,the PCP/AP and STA may select the minimum duration values from a set ofthe duration values, e.g. as follows:

-   -   aBRPminSCblocks={6 12 18}, {1, 2, . . . , 18}

Signaling used for negotiation may be based on the capability of theAP/PCP and the STA. In some embodiments, this may be communicated in acapability exchange procedure, e.g. in a transmission using AssociationRequest/Response, Re-association Request/Response, ProbeRequest/Response, Beacon frames, or other type of management frame. Insome embodiments, this may be communicated as a capability during theBRP setup procedure

IFS Optimization.

IFS has a significant effect on the efficiency of BRP feedback. As such,it is beneficial to optimize IFS to improve efficiency of BRP. Variousembodiments may use different techniques to optimize the IFS for theBRP. In some embodiments, the values of the IFS are negotiated. In otherembodiments, the IFS is restricted to the SIFS only.

IFS Negotiation.

In embodiments using IFS negotiation, the IFS may be selected as one ofa discrete set values. In such embodiments, the IFS may be selected froma set of pre-determined values. In some embodiments, the PCP/AP and STAmay negotiate a set of discrete resolutions such that SIFS<=IFS<=BRPIFS.

In an exemplary embodiment, a negotiation procedure may proceed asfollows. The BRPIFS may be communicated in a capability exchange, e.g. atransmission using Association Request/Response, Re-associationRequest/Response, Probe Request/Response, Beacon frames, or other typeof management frame. BRPIFS may be negotiated as part of the BRP setupnegotiation, at which time the antenna configuration is expected to havebeen communicated. If the negotiated value fails, the responder mayrespond by transmitting one or more PPDUs to the requesting STA e.g. anACK. The initiator may increment the IFS value for subsequentrefinements. The initiator may announce the IFS value to allow otherSTAs to know the IFS value for channel access.

Restrict the IFS to SIFS Only.

In an exemplary embodiment, the responder transmits a response to theinitiator after a SIFS duration on reception of the BRP measurementframe. If the response is available, the STA sends the response at aSIFS duration after the frame is received. If the response is notavailable, different options are available. In a first option, theresponder may respond by transmitting one or more PPDUs to therequesting STA (e.g. ACK) at a SIFS duration after the frame isreceived. An STA may contend for the channel at a later time and/or theAP may poll the STA at a later time. In a second option, the STA maytransmit dummy information until information is ready e.g L-STF.

As further examples, a method may include varying a maximum duration ofan interframe spacing between a plurality of BPR packets.

The method may further include signaling from a transmitter to areceiver to enable negotiation of values used for beam-based interframespacing parameters.

The parameters may include: short Beamforming Interframe Spacing; BeamRefinement Protocol Interframe Spacing; Medium Beamforming InterframeSpacing; and Long Beamforming Interframe Spacing.

A particular interframe spacing may be chosen based on particularconditions.

In an embodiment, a performed by an AP may include communicating with aplurality of STAs to obtain a respective BRP minimum duration for eachof the STAs; selecting a maximum value among the obtained BRP minimumdurations; and using the selected maximum value among them as the BRPminimum duration for DL MU-MIMO transmission to the STAs.

In an embodiment, a method of IFS negotiation may include, at an AP:sending an IFS measurement frame to at least one STA; sending a channelmeasurement frame to the at least one STA; receiving, from the at leastone STA, a respective estimated IFS duration; and performing a BRPprocedure using the received estimated IFS duration.

The AP may poll the at least one STA for the respective estimated IFSduration.

The BRP procedure may include sending a BRP setup frame identifying theIFS value to be used.

In an embodiment, a method includes negotiating an interframe spacing(IFS) between a PCP/AP and a STA. The IFS may be selected from apredetermined set of values.

Another example is a method of IFS negotiation that includes, at an AP:sending an IFS measurement frame to at least one STA; sending a channelmeasurement frame to the at least one STA; receiving, from the at leastone STA, a respective estimated IFS duration; and performing a BRPprocedure using the received estimated IFS duration. The AP may poll theat least one STA for the respective estimated IFS duration. Performingthe BRP procedure may include sending a BRP setup frame identifying theIFS value to be used.

Detailed Procedures with Fixed IFS.

To restrict the IFS to SIFS only, in the 11ay BRP protocol there shallbe an option in some embodiments for the BRP frame to function as anaction ACK frame.

Capability Exchange

In some embodiments, the capability of the STA may be signaled by in theBeamforming capability field format as shown below. The BeamformingCapability field may be implemented as show below:

TABLE 1 Beamforming Capability Field B0 B12 B4 B5 B6 B7 B8 B9 B10 B11B15 Requested MU-MIMO SU-MIMO Grant NoRSS BRP Action ACK with ACK withReserved BRP SC Supported Supported Required Supported ACK contentionpolling Blocks supported supported supported 5 1 1 1 1 1 1 1 5

The BRP Action ACK Supported field is set to one to indicate that theBRP request frame shall be responded to within a SIFS duration ofreception. If the information is ready the STA shall respond with theinformation required. If the information is not ready, the STA shallrespond with an ACK.

The ACK with contention Supported field is set to one if the STA maycontend for the channel when the information is ready to be fed back tothe requester and set to zero otherwise.

The ACK with polling Supported field is set to one if the STA may bepolled before feeding back the information to the requester and set tozero otherwise.

Note that the initiator may set the parameter to contend only, poll onlyor both.

These fields may be placed in separate capability fields or added todifferent frames such as the EDMG BRP Request field.

In another embodiment, the Beamforming capability field may be definedaccording to the following Beamforming Capability field format.

B0 B10 B12 B4 B5 B6 B7 B8 B11 B15 Requested MU-MIMO SU-MIMO Grant NoRSSBRP Reserved BRP SC Supported Supported Required Supported Action BlocksACK response 5 1 1 1 1 2 5

The BRP Action ACK response subfield indicates if the responding STAshould contend to feed back the information or the requesting STA shouldpoll the responding STA for the BRP information.

Action ACK response B10 B11 Reserved 0 0 Contention only 0 1 Pollingonly 1 0 Contention or Polling 1 1

Signaling Immediate Response Request: Method 1

In one method, the existing DMG action no ACK BRP frame may be modifiedto signal the need for an immediate acknowledgement in the BRP setupframe indicating that an ACK response is needed at a SIFS duration afterthe packet is received. The current 802.11 standard has a category ofUnprotected DMG frame with Type value 00 (management frame), and Subtypevalue 1110 (Action No ACK). The existing BRP frame is defined under theUnprotected DMG frame as an Action No Ack frame. The detailed frameformat of the BRP frame is given below:

Order Information 1 Category 2 DMG Action 3 Dialog Token 4 BRP RequestField 5 DMG Beam Refinement Element 6 Zero or more Channel MeasurementFeedback 7 EDMG BRP Request element (optional) 8 Zero or more EDMGChannel Measurement Feedback Elements 9 EDMG BRP Request Field

In exemplary embodiments, various different schemes may be used tosignal the immediate acknowledgement required in current BRP frame,including the following techniques.

-   -   1. Modifying the BRP Request Field (described below in the        section “Modified DMG BRP Request field”)    -   2. Modifying the EDMG BRP Request element (described below in        the section “Modified EDMG BRP Request element”)    -   3. Adding an EDMG BRP Request Field (described below in the        section “EDMG BRP Request field”)

Signaling Immediate Response Request: Method 2

In one method, an EDMG BRP frame is introduced and may be defined as aDMG action frame, which may be used to indicate an acknowledgement isneeded.

A new EDMG BRP frame may be introduced with Type value 00 (managementframe), and Subtype value 1101 (Action frame) under the category DMGframe. In order to do so, one entry may be inserted to DMG Action field.For example, DMG Action field value=23 may be used to indicate that theframe is an EDMG BRP frame.

DMG Action Field DMG Action field Value: Meaning: 23 EDMG BRP Frame

The detailed EDMG BRP frame format may be as disclosed below:

EDMG Action ACK BRP Frame Order Information 1 Category 2 DMG Action 3Dialog Token 4 BRP Request Field 5 DMG Beam Refinement Element 6 Zero ormore Channel Measurement Feedback 7 EDMG BRP Request element (optional)8 Zero or more EDMG Channel Measurement Feedback Elements 9 EDMG BRPRequest Field

In an exemplary embodiment, the Category field is defined as DMG. TheDMG Action field is defined as EDMG BRP frame. The Dialog Token field isset to a value chosen by the STA sending the frame to uniquely identifythe transaction. The BRP Request field may be defined as existing instandard. Alternatively, this field may be updated, as described in thesection “Modified DMG BRP Request field.” The DMG Beam Refinementelement is defined in 9.4.2.130 of 802.11-2016. The Channel MeasurementFeedback element is defined in 9.4.2.136.

The BRP frame contains more than one Channel Measurement Feedbackelement if the measurement information exceeds 255 octets. The contentof each Channel Measurement Feedback element that follows the first onein a single BRP frame is a continuation of the content in the previouselement. The Channel Measurement, Tap Delay, and Sector ID Ordersubfields can be split between several elements. Each ChannelMeasurement Feedback element that is not the last Channel MeasurementFeedback element in the frame is 257 octets long. Channel measurementinformation for a single channel measurement is always contained withina single BRP frame.

It may be noted that the length of a BRP frame can limit the choice ofchannel measurement parameters such as the number of measurements andthe number of taps.

EDMG BRP Request element may be defined as it is. Alternatively, thisfield may be modified as described in the section “Modified EDMG BRPRequest element.” In some embodiments, the EDMG BRP Request Field may bea newly inserted field, as described in the section “EDMG BRP Requestfield.”

Signaling Immediate Response Request: Method 3

In one exemplary method, the existing DMG action no ACK BRP frame may bemodified to signal the need for an immediate acknowledgement in the BRPsetup frame indicating that an ACK response is needed at a SIFS durationafter the packet is received. The current 802.11 standard has a categoryof Unprotected DMG frame with Type value 00 (management frame), andSubtype value 1110 (Action No ACK). The existing BRP frame is definedunder the Unprotected DMG category as an Action No Ack frame. The BRPframe in this case is an Action or Action no ACK frame of categoryUnprotected DMG. In some embodiments, the existing BRP frame setting ismodified from Subtype value=1110 (Action No ACK) to Subtype value=1101(Action), and the rest of the parameter settings are kept to create anew EDMG Action ACK frame.

When performing BRP, if the BRP frame is a Management frame of subtypeAction and if a responding STA requires longer than SIFS to transmit aBRP frame as a response for beam refinement training request from arequesting STA, the STA transmits an ACK frame or an EDMG BRP ACK framein response to the beam refinement training request.

To send the BRP response to the requesting STA:

The requesting STA may send a feedback poll to request for the response.

The responding STA may contend for the medium and send back theresponse.

The requesting STA may allocate time for the feedback through a reversedirection grant, provided the reverse direction protocol is supported byboth the requesting and responding STAs.

The BRP response method maybe selected during the BRP setup phase. TheSTA may indicate the additional time needed in the EDMG BRP ACK.

The BRP setup subphase may start with the initiator sending a BRP packetwith the Capability Request subfield in the DMG Refinement field set to1 and with the remaining subfields within the BRP Request field/EDMGRequest field set according to the initiator's desired response method.Upon receiving a BRP packet with the Capability Request subfield set to1, the responder shall respond with a BRP packet with the subfieldswithin the BRP Request field set to indicate the desired BRP responsemethod. This process is repeated until the responder transmits to theinitiator a BRP packet with the Capability Request subfield set to 0 andthe initiator sends as a response a BRP packet with the CapabilityRequest subfield also set to 0.

A detailed frame format of an exemplary BRP frame is given below:

Order Information 1 Category 2 DMG Action 3 Dialog Token 4 BRP RequestField 5 DMG Beam Refinement Element 6 Zero or more Channel MeasurementFeedback 7 EDMG BRP Request element (optional) 8 Zero or more EDMGChannel Measurement Feedback Elements 9 EDMG BRP Request Field

In an exemplary method, different techniques may be used to signal theimmediate acknowledgement required in current BRP frame, including thefollowing:

-   -   1. Modifying BRP Request Field (as described in the section        “Modified DMG BRP Request field”)    -   2. Modifying EDMG BRP Request element (as described in the        section “Modified EDMG BRP Request element”)    -   3. Add EDMG BRP Request Field (as described in the section “EDMG        BRP Request field”)

Modified EDMG BRP Request Element

In some embodiments, in both the Action and no Action BRP frame, theEDMG BRP request element may be updated as follows:

B0 B8 B16 B24 B32 B40 B51 B53 B57 B60 B7 B15 B23 B31 B39 B50 B52 B56 B58B59 B61 B62 B63 Element ID Length Element ID IL-RX L-TX- TX Sector EDMGEDMG EDMG Action Action ACK BF Poll Reserved Extension RX ID TRN-UnitTRN-Unit TRN-Unit ACK response P M N

The Action ACK subfield indicates if an acknowledgement is required aSIFS duration after the transmission of the request. When this field isset to 0, a response is not required a SIFS duration after the receptionof the request. Instead, a response is required within a BRPIFS durationafter the reception of the request. When the field is set to 1, aresponse is required a SIFS duration after the reception of the request.

In the case that the response is ready, the response serves as anacknowledgement. In the case that the response is not ready, an ACK maybe sent as a response. Alternatively, this field may not present. Notethat this field is best suited for method 1 that uses a single DMGaction No ACK frame to signal the need for an ACK or not. For method 2and 3 that define specific Action ACK frames, this field may beoptional.

The Action ACK response subfield may be used to indicate if theresponder should contend to feed back the information or the respondershould be polled.

Action ACK response B60 B61 Reserved 0 0 Contend for channel only 0 1Polling only 1 0 Contend and Poll 1 1

The BF Poll field indicates that there are no additional TRN fields sentbut that this is a request for feedback for a previously transmitted BRPrequest with exactly the same parameters. In another embodiment, the TXSector ID may be used as an identifier in the feedback to indicate thespecific BRP transmission the feedback is for (for example, incontention based transmission).

Given that a reasonable estimate of the time duration required beforethe feedback is ready depends on the information requested and the EDMGantenna configuration, a timing estimate may be sent back with theacknowledgement frame. In one method, the ACK may include a controltrailer to indicate the length of time needed before the information isready. In this case, for the transmitted ACK frame, the TXVECTORparameter CONTROL_TRAILER shall be set to Present and the parameterCT_TYPE shall be set to ACK. The control trailer in this case may be asingle data octet. Alternatively, an EDMG BRP ACK may be sent thatincludes the time needed.

EDMG BRP Request Field

Alternatively, in some embodiments, an EDMG BRP Request field may bedefined to carry acknowledgement related information. In both the Actionand no Action BRP frame, the EDMG BRP Request field may be updated asfollows:

B0 B1 B2 B3 B4 B7 Action ACK Action ACK response BF Poll Reserved 1 2 14

The Action ACK subfield indicates if an acknowledgement is required aSIFS duration after the reception of the request. When this field is setto 0, a response is not required a SIFS duration after the reception ofthe request. Instead, a response is required within a BRPIFS durationafter the reception of the request. When the field is set to 1, aresponse is required a SIFS duration after the reception of the request.In the case that the response is ready, the response serves as anacknowledgement. In the case that the response is not ready, an ACK maybe sent as a response. Alternatively, this field may not present.

The Action ACK response subfield indicates if the responder shouldcontend to feed back the information or the responder should be polled.

Action ACK response B60 B61 Reserved 0 0 Contend for channel only 0 1Polling only 1 0 Contend and Poll 1 1

The BF Poll field indicates that there is no additional TRN fields sentbut that this is a request for feedback for a previously transmitted BRPrequest with exactly the same parameters. In another embodiment, the TXSector ID may be used as an identifier in the feedback to indicate thespecific BRP transmission the feedback is for (for example, incontention based transmission).

Modified DMG BRP Request Field

Alternatively, the existing DMG BRP Request field may be modified tocarry acknowledgement related information.

B0 B11 B17 B25 B29 B4 B5 B6 B7 B8 B9 B10 B16 B24 B26 B27 B28 B30 B31L-RX TX-TRN- MID- BC- MID- BC- Chan- TX Sector Other_AID TX antennaAdditional Action Action ACK BF Poll REQ REQ REQ Grant Grant FDCK- ID IDFeedback ACK response CAP Requested

The Action ACK subfield indicates if an acknowledgement is required aSIFS duration after the reception of the request. When this field is setto 0, a response is not required a SIFS duration after the reception ofthe request. Instead, a response is required within a BRPIFS durationafter the reception of the request. When the field is set to 1, aresponse is required a SIFS duration after the reception of the request.In the case that the response is ready, the response serves as anacknowledgement. In the case that the response is not ready, an ACK maybe sent as a response. Alternatively, this field may not present.

The Action ACK response subfield indicates if the responder shouldcontend to feed back the information or the responder should be polled.

Action ACK response B60 B61 Reserved 0 0 Contend for channel only 0 1Polling only 1 0 Contend and Poll 1 1

The BF Poll field indicates that there is no additional TRN fields sentbut that this is a request for feedback for a previously transmitted BRPrequest with exactly the same parameters. In another embodiment, the TXSector ID may be used as an identifier in the feedback to indicate thespecific BRP transmission the feedback is for (for example, incontention based transmission).

In one embodiment, the requesting and responding STAs may decide on adefault method of feedback e.g. Contention or polling. The Action ACKresponse may then be a single bit indicating if the non-default methodis supported. This may be signaled in the Modified EDMG BRP Requestelement, the EDMG BRP request field or the beamforming capability field.

Action ACK response B60 Non-default method NOT supported 0 Non-defaultmethod supported 1

EDMG BRP ACK Frame Format

A normal ACK frame may be used when the BRP response may not be ready ina SIFS duration after the reception of the BRP frame.

Alternatively, a newly defined EDMG BRP ACK frame may be used to carryadditional information, such as estimated time to prepare the requiredBRP feedback. The EDMG BRP ACK frame may be defined below:

TABLE 2 EDMG BRP ACK Octets: 2 2 6 1 4 Frame Control Duration RA TimeEstimate FCS

In a third method, a normal ACK frame may be carried in a control modePPDU where a control trailer may be appended as shown below:

TABLE 3 ACK for BRP with Control Trailer Octets: 2 2 6 4 1 (Trailer)Frame Control Duration RA FCS Timing Estimate

The Duration field is set as defined in 9.2.5 of 802.11-2016.

The RA is set to the recipient STA that requested the BRP transmission.The Time estimate is the minimum time duration that the recipient STAshall delay before:

The requesting STA may poll for the BRP response

The requesting STA may set up a reverse direction protocol link

The requesting STA may set a CBAP to allow the transmitter to contendfor the channel

The Time estimate may indicate the number of SIFS that the recipient STAshould wait. Note that as the upper bound may be set as the legacyBRPIFS value (44 usecs) or approximately 15 SIFS durations (of 3 usecseach) or may be set to an arbitrary value. In one solution, the timeduration may be set to 2*SIFS (6 usec)<interval<15*SIFS (45 usec) andthe specific value signaled with 4-bits as shown in the figure below.Note that 15*SIFS entry defaults to a wait time of BRPIFS as in DMGbehavior.

TABLE 4 ACK Delay Representation Duration 0000 Reserved 0001 2*SIFS 00103*SIFS 0011 4*SIFS 0100 5*SIFS 0101 6*SIFS 0110 7*SIFS 0111 8*SIFS 10009*SIFS 1001 10*SIFS 1010 11*SIFS 1011 12*SIFS 1100 13*SIFS 1101 14*SIFS1110 15*SIFS = BRPIFS 1111 Reserved

In one exemplary embodiment, the entire 8 bits may be used to quantizethe 44 usec interval. Alternatively, the duration may be represented inusecs as in the duration field (e.g. 256 usecs).

In order to define an EDMG BRP ACK frame, a control frame extensionvalue may be set to indicate the newly defined frame. For example, inthe proposed EDMG BRP ACK frame, Type value in Frame Control field maybe set to 01 to indicate a control frame. Subtype value in Frame Controlfield may be set to 0110 to indicate control frame extension. With aControl Frame Extension subtype, bit 8 to bit 11 may be set to certainvalue to indicate the EDMG BRP ACK frame. For example, the followingsetting may be utilized:

Control Frame Type value Subtype value Extension value B3 B2 B7 B6 B5 B4B11 B10 B9 B8 Description 01 0110 1011 EDMG BRP ACK

Procedures and Signaling for Polling Based BRP Feedback

In the case an ACK frame may be transmitted a SIFS duration after thereception of the BRP request frame, the BRP feedback frame which maycarry the information requested by the previous BRP request frame may betransmitted through a polling based procedure. In this procedure, aframe may be used to poll the BRP feedback frame.

For polling based feedback, the following techniques may be used.

In some embodiments for polling based feedback, BF poll is used. Toenable this, a unique BF identifier may be generated from the fields ofthe BF request. The BF poll and BF feedback response may use this uniqueidentifier to identify the specific feedback. The identifier may beplaced in the BRP Feedback

Order Information 1 Category 2 DMG Action 3 Dialog Token 4 BRP FeedbackPoll Request

Order Information 1 Category 2 DMG Action 3 Dialog Token 4 BRP FeedbackPoll Response 5 Zero or more Channel Measurement Feedback 6 Zero or moreEDMG Channel Measurement Feedback Elements

In other embodiments, for polling based feedback, an updated BR requestframe may be used with a parameter added to indicate that the request isfor a previously sent BRP request as discussed above. The BF pollresponse may use a unique identifier. Alternatively, the EDMG BRPrequest may be transmitted with the response. In this case, all or someof the fields of the BRP frames are transmitted. The scenario is which asubset of the frames are transmitted is illustrated below.

Order Information 1 Category 2 DMG Action 3 Dialog Token 5 DMG BeamRefinement Element 7 EDMG BRP Request element (optional) 8 Zero or moreEDMG Channel Measurement Feedback Elements

For contention based feedback, the PCP/AP may set up a general CBAPduring the DTI for feedback. Alternatively, the PCP/AP may set up adedicated CBAP for feedback during the DTI that is restricted to theSTAs that have sent an ACK. The PCP/AP may transmit the addresses of theSTAs that may be allowed to contend during this period.

Procedures and Signaling for BRP Feedback without Polling

In the case an ACK frame may be transmitted a SIFS duration after thereception of the BRP request frame, the BRP feedback frame which maycarry the information requested by the previous BRP request frame may betransmitted through a BRP feedback procedure without polling.

The BRP initiator may transmit a BRP frame requesting a BRP training. Inthe BRP frame, the initiator may indicate a response a SIFS durationafter the reception of the BRP frame may be requested.

On reception of the BRP frame, the responder may not have enough time toprepare the requested BRP response frame.

-   -   The responder may transmit an ACK frame a SIFS duration after        the reception of the BRP frame transmitted by the initiator.    -   The responder may transmit a response frame which carry the        requested information a BRFIFS duration after the reception of        the BRP frame transmitted by the initiator.        -   Before transmitting the BRP response frame, the responder            may operate to sense the channel. If the channel is free in            a predefined/predetermined period, the BRP response frame            may be transmitted. In one method, the STA may not need to            defer additional backoff period set by an EDMA backoff            timer.        -   In the case the STA may not be able to successfully transmit            the BRP response frame within a BRPIFS duration from the end            of BRP request frame transmitted by the initiator, the STA            may (i) wait for a SP assigned to the STA to transmit; (ii)            wait for next CBAP to content to transmit; or (iii)            aggregate the BRP response frame with other data, control or            management frames and transmit them to the initiator.    -   Alternatively, the responder may transmit a response frame which        carry the requested information a T duration after the reception        of the BRP frame transmitted by the initiator. Here        SIFS<=T<+BRPIFS.        -   Before transmitting the BRP response frame, the responder            may need to sense the channel. If the channel is free in a            predefined/predetermined period, the BRP response frame may            be transmitted. In one method, the STA may not need to defer            additional backoff period set by an EDMA backoff timer.        -   In the case the STA may not be able to successfully transmit            the BRP response frame within a BRPIFS duration from the end            of BRP request frame transmitted by the initiator, the STA            may (i) wait for a SP assigned to the STA to transmit; (ii)            wait for next CBAP to content to transmit; or (iii)            aggregate the BRP response frame with other data, control or            management frames and transmit them to the initiator.

An exemplary embodiment of a procedure and signaling for BRP feedbackwithout polling is illustrated in FIG. 34 , which illustrates IFS 3402.

Procedures and Signaling with BRP Response Time Capability Exchanges

Alternatively or additionally, the beamforming field may contain anindication of a STA's capabilities in providing feedback after receivinga BRP frame. For example, a STA may indicate its capabilities ofexpected time to transmit a response frame after receiving a BRP frame.One or more bits in the EDMG Capability field, e.g., in the beamformingfield, may be used to indicate the expected BRP response time. In oneembodiment, a bit may be used to indicate the presence of expected BRPresponse time. The Expected BRP response time may be indicated by one ormore bits, and may be indicated in the terms of us, in terms of SIFS,and in terms of any other time units. In one embodiment, a STA mayindicate multiple Expected BRP response time, e.g., in the EDMGCapability field, e.g., in the Beamforming field. For example, a STA mayindicate Expected BRP response time for SU and/or MU MIMO training, aSTA may indicate Expected BRP response time for one or more spatialstreams.

A STA may exchange its capability of or one or more of its Expected BRPResponse Times during the association process with an AP, for example,in the Probe Request, (Re)Association frames. An AP/PCP may announce itsown capability of or one or more its Expected BRP Response Times in itsbeacon, and/or in a Probe Response, (Re)Association Response frames.Additionally, an AP/PCP may announce the one or more largest ExpectedBRP Response Time(s) for all STAs that are associated with it. Forexample, an AP/PCP may announce the largest Expected BRP Response timefor all STAs associated with it; in another example, an AP/PCP mayannounce the largest Expected BRP Response time SU and/or MU MIMO forall STAs that are associated with it; in another example, an AP/PCP mayannounce the largest Expected BRP Response time for one or more spatialstreams for all STAs that are associated with it. A STA, after receivingfrom its AP/PCP, for example, in a beacon, Probe Response,(Re)Association Response frame, may adapt the one or more largest BRPResponse Times in its BRP protocols.

Additionally and/or alternatively, a STA may indicate in a frame settingup the BRP exchange sequence that the appropriate BRP Response timeshould be applied. For example, an AP/PCP may indicate the appropriateBRP Response time to be used for the BRP exchange sequence, e.g., in theExtended Schedule element or Grant frame. The AP/PCP may derive thelargest BRP Response time needed by all STAs that will provide feedback.The AP/PCP may derive the largest BRP Response time needed by all STAsthat will provide feedback for SU, MU training, one or more SS feedbacketc., e.g., based on the information that the AP/PCP has obtainedearlier, e.g., during the association process, or during the BRP requestor Service Period Request time. For example, if 4 STAs are providingfeedback in a MU MIMO training, the largest expected BRP response timewill be the largest expected BRP response time among all 4 STAs. If boththe initiator and the responders may provide feedback, then the largestExpected BRP response time may be the largest Expected BRP Response timeamong the initiator and the responder STAs.

If a responder STA indicates a need for training as a response to anSSW-Feedback, it may indicate its one or more expected BRP Responsetime(s) in the BRP Request field in, e.g., the SSW-ACK frame. Theinitiator may use the indicated most appropriate BRP Response times inthe BRP execution that it will initiate subsequently.

The AP/PCP and/or the initiator may announce the applied BRP responsetime to be used in the upcoming BRP sequence exchanges. If the responderhas not been capable to provide a feedback, it may respond by an ACKframe. It may also adding an expected BRP response time in the ACK. Ifthe expected BRP response time in the ACK sent by the responder islonger than the announced BRP response time by the AP/PCP or theinitiator, the initiator may adjust the BRP response time in subsequentBRP frames.

In one embodiment, if the responding STA is not ready to send the BRPresponse at the expiration of the SIFS duration, the STA sends an ACK tothe requesting STA. The requesting STA may request for the informationat or greater than a BRPIFS duration after the reception of the ACK.Alternatively, the requesting STA may request for the information at orgreater than a BRPIFS duration after the reception it estimates that thetransmitted packet arrived at the responding STA. This eliminates theneed for any additional timing information.

Defining BRP Action ACK Frame

In an exemplary embodiment, if the BRP frame is a Management frame ofsubtype Action, a beam refinement response shall be separated from apreceding beam refinement request by a SIFS interval provided sufficienttime is available for the complete transmission of those frames withinthe SP allocation or TXOP. The response serves as an implicit ACK.

When performing BRP, if the BRP frame is a Management frame of subtypeAction and if a responding STA requires longer than SIFS to transmit aBRP frame as a response for beam refinement training request from arequesting STA, the STA shall transmit an ACK frame (9.3.1.4) or an EDMGBRP ACK frame (9.3.1.22) in response to the beam refinement trainingrequest.

To send the BRP response to the requesting STA:

-   -   The requesting STA may send a feedback poll to request for the        response.    -   The responding STA may contend for the medium and send back the        response.    -   The requesting STA may allocate time for the feedback through a        reverse direction grant, provided the reverse direction protocol        is supported by both the requesting and responding STAs.

The BRP response method maybe selected during the BRP setup phase.

The STA may indicate the additional time needed in the EDMG BRP ACK.

As further examples, a method performed by a BRP responder may include:receiving a BRP measurement frame from an initiator; determining whethera response to the BRP measurement frame is available within a SIFS ofthe reception of the BRP measurement frame; in response to adetermination that the response is not available within a SIFS of thereception of the BRP measurement frame; transmitting an ACK at the endof the SIFS; and subsequently transmitting a response to the BRPmeasurement frame. The subsequent transmitting may be performed usingchannel contention. The subsequent transmitting may be performed byusing a traffic available frame to request channel access. Thesubsequent transmitting may be performed in response to being polled bythe initiator.

As another example, a method performed by a BRP responder may include:receiving a BRP measurement frame from an initiator; determining whethera response to the BRP measurement frame is available within a SIFS ofthe reception of the BRP measurement frame; in response to adetermination that the response is not available within a SIFS of thereception of the BRP measurement frame; transmitting an ACK at the endof the SIFS, wherein the ACK identifies a time interval; receiving apolling frame from the initiator after passage of the identified timeinterval; and transmitting a response to the BRP measurement frame inresponse to the polling.

As another example, a method performed by a BRP responder may include:receiving a BRP measurement frame from an initiator; determining whethera response to the BRP measurement frame is available within a SIFS ofthe reception of the BRP measurement frame; in response to adetermination that the response is not available within a SIFS of thereception of the BRP measurement frame; initiating a transmission to theinitiator using dummy data; and subsequently continuing the transmissionto the initiator including a response to the BRP measurement frame.

As another example, a method may include negotiating a minimum duration(aBRPminSCblocks) between a PCP/AP and a STA. The minimum duration maybe selected from a predetermined set of values.

Notes on Embodiments.

Although the features and elements of the present disclosure aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present disclosure.

Although the solutions described herein consider 802.11 specificprotocols, it is understood that the solutions described herein are notrestricted to this scenario and are applicable to other wireless systemsas well.

Throughout the solutions and provided examples, any blank areas in thefigures, e.g., white space, etc., implies that there is no restrictionfor this area and any solution can be employed.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable storage media include, butare not limited to, a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs). A processor in association with software may be used toimplement a radio frequency transceiver for use in a WTRU, UE, terminal,base station, RNC, or any host computer.

We claim:
 1. A method of performing a beam refinement protocol (BRP),comprising, at a responder: receiving a BRP measurement frame from aninitiator of the BRP; generating feedback regarding the BRP measurementframe; and transmitting a response to the BRP measurement frame within apredetermined time of receipt of the BRP measurement frame, including,transmitting the feedback if the feedback is available within thepredetermined time of receipt of the BRP measurement frame; andtransmitting information in acknowledgement of receipt of the BRPmeasurement frame if the feedback is not available within thepredetermined time of receipt of the BRP measurement frame.